JP6907569B2 - Image forming device, program, setting method - Google Patents

Description

The present invention relates to an image forming apparatus, a program, and a setting method.

The image forming apparatus forms an image on paper and prints it, but it is known that the optimum setting at the time of printing differs depending on the type of paper. For example, since heat transfer is different between plain paper and coated paper, the image forming apparatus controls the temperature of the fuser and changes the paper transport speed depending on whether the plain paper or coated paper is used. In this way, the print quality can be improved by changing the setting depending on the type of paper.

Therefore, a technique has been proposed in which an image forming apparatus assists an appropriate setting based on paper (see, for example, Patent Document 1). Patent Document 1 discloses a fax machine that, when it detects that paper has been loaded in the paper feed unit, inquires of the user about the type of the loaded paper and prints according to the type of paper set by the user. There is.

However, the paper-based setting method described in Patent Document 1 has a problem that it may not be possible to appropriately set the paper for printing based on the paper used by oneself. First, the technique described in Patent Document 1 can only handle paper types in which the paper size and thickness are determined only by the paper type. For example, with a paper type in which the paper size and thickness are fixed, such as label printing, it is possible to appropriately print only the paper type set by the user.

On the other hand, for papers having the same paper type but having various thicknesses and sizes, such as plain paper and coated paper, it is difficult to set an appropriate paper only by the paper type. For example, most of the paper used for printing is plain paper, and it is common practice to choose the size of plain paper. However, there are various thicknesses (basis weights) of plain paper, and it is not well known that the thickness can be set. Further, for example, when using coated paper, even if the user knows that it is necessary to select the coated paper and set the thickness, it may not be possible to correctly set the thickness.

Even if the user does not set the size and thickness of the paper, if the image forming apparatus senses the characteristics of the paper such as the size and thickness of the paper, the setting based on the paper can be appropriately performed. However, it is actually difficult to use an image forming apparatus equipped with a sensor for detecting each characteristic because the cost increases.

In view of the above problems, an object of the present invention is to provide an image forming apparatus that supports setting of a sheet material based on the sheet material used.

The present invention is an image forming apparatus that forms an image on the sheet material based on the sheet material setting related to the sheet material, and is a receiving means for accepting selection of the sheet material type and a thickness measurement for measuring the thickness of the sheet material. and means, based on the thickness of the receiving unit is the sheet material type and the thickness measuring means has measured the reception has a setting determining means for determining the sheet settings for the thickness of the sheet material After the measured thickness of the sheet material changes by a threshold value or more, the thickness measuring means rotates the roller for one round to detect the eccentric component of the roller, and the eccentric component is detected from the thickness of the sheet material. When the eccentric component measured after the start of image formation is larger than the eccentric component measured before the start of image formation, a failure detecting means for detecting a failure of the thickness measuring means is provided. Have.

It is possible to provide an image forming apparatus that assists in setting a sheet material based on the sheet material used.

This is an example of a diagram schematically illustrating a procedure in which an image forming apparatus sets paper. This is an example of a schematic configuration diagram of an image forming apparatus. This is an example of a hardware configuration diagram of an image forming apparatus. It is an example of the figure explaining the paper size detection sensor of a paper feed unit. It is an example of the figure explaining the paper size detection sensor of a manual feed tray. It is an example of the figure explaining the structure of the paper thickness detection sensor. This is an example of a functional block diagram for explaining the function of the image forming apparatus. This is an example of a flow chart showing the flow until the paper setting is determined. It is a figure which shows an example of the paper type selection screen. It is an example of the figure schematically explaining the determination of the paper size and the paper thickness. This is an example of a diagram showing the relationship between the paper thickness and the basis weight of each paper type. This is an example of a diagram for explaining the relationship between the paper thickness and the basis weight of the paper whose paper thickness type is determined by the paper type. This is an example of a diagram for explaining the correlation coefficient of the conversion formula. This is an example of a flowchart showing a procedure in which the image forming apparatus sets the paper. It is a figure which shows an example of the paper setting inquiry screen. It is a figure explaining an example of the control of the image forming apparatus according to a paper setting. This is an example of a functional block diagram for explaining the function of the image forming apparatus (Example 2). This is an example of a diagram schematically showing a method of correcting the paper thickness. This is an example of a diagram for explaining the correction timing of the paper thickness. This is an example of a flowchart showing a procedure in which the control parameter changing unit changes the control parameter. This is an example of a flowchart showing a procedure in which the control parameter changing unit changes the control parameter. This is an example of a flowchart showing a procedure in which the failure detection unit detects a failure of the paper thickness detection sensor.

Hereinafter, the image forming apparatus and the method of setting the paper setting performed by the image forming apparatus, which is a mode for carrying out the present invention, will be described with reference to the drawings.

FIG. 1 is an example of a diagram schematically illustrating a procedure in which the image forming apparatus of the present embodiment sets paper.

(1) When the user prints, the image forming apparatus inquires the user about the type of paper to be printed. For example, a paper type selection screen for inquiring about the paper type is displayed on an operation panel or the like. One of the features of the present embodiment is that a paper type that can be visually and intuitively determined by the user is displayed on the paper type selection screen. The image forming apparatus displays only the paper type that can be determined without considering the thickness and paper size information so that the user can intuitively select the paper type. When the user selects a paper type, the image forming apparatus accepts the paper type selected by the user.

(2) Next, the image forming apparatus measures the vertical and horizontal dimensions (length) of the paper.

(3) Once the vertical and horizontal dimensions of the paper are known, it is possible to determine the paper size that matches the vertical and horizontal dimensions by referring to a table or the like in which the dimensions and the paper size are associated. Since the paper types have already been narrowed down by the user's selection, one of the features is that it is easy to determine the paper size.

(4) Further, the image forming apparatus measures the thickness of the paper.

(5) When the thickness is known, the image forming apparatus converts the thickness measured by using the conversion formula for converting the thickness into the basis weight. There is a strong correlation between paper thickness and basis weight for each paper type, and conversion formulas are created for each paper type selected by the user. Therefore, one of the features is that by measuring the thickness of the paper, it is possible to convert the basis weight to the correct one for this paper type.

(6) Once the basis weight is known, the image forming apparatus can determine the paper thickness type from the basis weight by referring to a table or the like in which the basis weight and the paper thickness type are associated with each other.

The image forming apparatus sets the paper in the image forming apparatus based on the paper size and the paper thickness type determined by the image forming apparatus. That is, since the paper size and the paper thickness type are determined, the transport speed, the fixing temperature, the bias voltage, and the like can be appropriately set.

On the other hand, when the image forming apparatus measures the paper dimensions and the paper thickness to set the paper, the vertical and horizontal dimensions of the paper are measured in units of 1 [mm], and the weight of one sheet of paper is also measured. Must be measured accurately. This is because it is premised that there are different types of paper having similar dimensions, and that one sheet of paper is light but takes up space and is difficult to measure. Therefore, the sensor cost increases, and the mechanical cost for operating the sensor properly increases.

On the other hand, in the present embodiment, since the paper type is first selected from the list of paper types that can be intuitively determined by the user, it is difficult to make a mistake in the paper type. Further, since the user narrows down the paper type, it is easy to narrow down the paper size according to the paper type. Similarly, the user can select different thickness and basis weight conversion formulas depending on the paper type in order to narrow down the paper type, and the thickness can be converted to the basis weight. In addition, paper settings (paper size, paper thickness type, etc.) can be determined accurately without using a high-precision sensor.

<Terminology>
A sheet material is a sheet-like member used for printing purposes. It can be a sheet material if it is supplied to an image forming apparatus and can be discharged. The sheet material is paper, OHP, plastic film, prepreg, copper foil, or the like. In this embodiment, the term “paper” will be used.

The sheet material setting related to the sheet material is a setting determined by the sheet material among the settings for the image forming apparatus. The image forming apparatus performs optimum control according to the sheet material setting. For example, the sheet material size and the sheet material thickness type are the sheet material settings related to the sheet material. Further, the sheet material type may be included in the sheet material setting. In addition, smoothness and Young's modulus can also be included in the sheet material setting. In the present embodiment, the sheet material setting will be described by the term paper setting.

The sheet material setting regarding the thickness of the sheet material is a sheet material setting that is affected by the thickness of the sheet material among the sheet material settings. The image forming apparatus divides the thickness into several groups (the basis weight of the paper thickness table in Table 2 described later), and specifically, the sheet material thickness type that is the name of this group is the sheet material. The sheet material setting regarding the thickness can be mentioned. In addition, the basis weight and Young's modulus that correlate with the thickness of the sheet material can be mentioned. It should be noted that the basis weight is divided into groups because a constant print quality can be obtained without finely dividing the control, and the basis weight may be used as it is as the sheet material setting regarding the thickness of the sheet material.

The sheet material type is a classification of sheet materials determined by the characteristics of the sheet material and the like. Specifically, the characteristics of the sheet material are evaluated by dimensions, thickness, basis weight, density, Young's modulus, smoothness, appearance and the like. In the present embodiment, the sheet material type will be described by the term paper type.

The thickness of the sheet material is the length (dimension) in the thickness direction. The basis weight is the weight of the sheet material per unit area. The thicker the thickness, the larger the basis weight, so there is a correlation between the two. However, this correlation often differs depending on the type of sheet material.

The thickness type of the sheet material is the type of thickness classified according to the basis weight. Specifically, there are plain paper, thin paper, medium-thick mouth, thick paper 1, thick paper 2, thick paper 3, and the like.

The sheet material size is the type, name, name, etc. of the sheet material size. The size of the sheet material is determined by the standard, the practical standard of the industry, etc., and in many cases, the standard size is determined for each type of sheet material. For example, in the case of plain paper, A3, A4, B4 and the like are the sheet material sizes, and in the case of envelopes, the square 2 type and the long type 3 are the sheet material sizes. In the present embodiment, the sheet material size will be described by the term paper size.

<Configuration example>
FIG. 2 is an example of a schematic configuration diagram of an image forming apparatus. The image forming apparatus 10 of FIG. 2 is an apparatus called a digital multifunction device, and has a copying function, a printer function, a facsimile function, a scanner function, and the like. The application switching key on the operation panel 20 allows the user to arbitrarily switch and select the copying function, the printer function, the facsimile function, and the scanner function. When the user selects the copy function, the image forming apparatus 10 is in the copy mode, and when the printer function is selected, the image forming apparatus 10 is in the printer mode. When the user selects the facsimile mode, the facsimile mode is set, and when the scanner mode is selected, the scanner mode is set.

The image forming apparatus 10 includes an automatic document feeder 11 (ADF: Auto Document Feeder), an image reading device 12, a writing unit 13, an image forming engine 14, an operation panel 20, a fixing device 16, a manual feed tray 17, and two feeders. It has a paper unit 15.

The operation panel 20 is an input / output unit in which a touch panel is formed on a display such as a liquid crystal or an organic EL. The operation panel 20 displays various information and soft keys, and accepts user operations. Around the operation panel 20, some hard keys including a start button for receiving a start of printing are arranged.

The automatic document feeder 11 takes out the placed documents one by one, feeds them on the contact glass, and when the image reading device 12 reads the paper, ejects the paper to the output tray. The image reading device 12 illuminates the document on the contact glass while moving the exposure lamp mounted on the carriage, and forms an image of the document on a line sensor such as a CCD via a lens, a mirror, or the like. The image reading device 12 applies shading correction, MTF correction, gamma correction, and the like to the image, and the image data (digital data) to which these processings have been performed is temporarily stored in a storage means such as a RAM.

The image forming engine 14 includes a photoconductor drum 19 which is an image carrier, a developing device 18, and the like. The photoconductor drum 19 is rotationally driven clockwise in the figure, and the surface is charged to a predetermined potential by a charging device. The writing unit 13 irradiates the photoconductor drum with a laser beam modulated based on the image data. As a result, an electrostatic latent image is formed on the surface of the photoconductor drum 19. The developing device 18 is a device that adsorbs toner corresponding to the electrostatic latent image on the surface of the photoconductor drum 19. This toner is transferred to the paper.

The paper feed unit 15 stores various types of paper, and one of the paper feed units 15 that stores the paper selected by the user feeds the paper to the transport path 22 by the paper feed roller 15a. The transport path 22 has several transport rollers 22a, and transports the paper to the photoconductor drum 19. The fixing device 16 is a device that fixes a toner image on paper by heat and pressure.

The bypass tray 17 is a paper feeding means for the user to print on arbitrary paper. In addition to being able to feed plain paper, it is also used when relatively thick paper and envelopes are being fed. A paper thickness detection sensor 21 is arranged between the paper feed roller 17a and the transport roller 22a of the bypass tray 17. The paper thickness detection sensor 21 is a sensor that measures the thickness of paper. Details will be described later in FIG. The paper thickness detection sensor 21 may be further arranged between the paper feed roller 15a and the paper feed roller 22a of the paper feed unit 15. As a result, the image forming apparatus 10 can measure the thickness of the paper fed from the paper feeding unit 15.

Further, the manual feed tray 17 has a paper size detection sensor. The paper size detection sensor is a sensor that measures the vertical and horizontal dimensions of paper. Details will be described later in FIG. The paper size detection sensor is also arranged in the paper feed unit 15. Details of the paper size detection sensor of the paper feed unit 15 will be described later in FIG.

The operation procedure of the image forming apparatus 10 for forming an image will be briefly described by taking a copying mode as an example. First, the user sets how to print in the copy mode from the operation panel 20. For example, paper (type, size, thickness), density setting, scaling setting, aggregation setting, etc. can be set. A bundle of documents placed on the automatic document feeder 11 is sequentially fed to the contact glass. The original is fed to the image reading device 12, and is read as image data by the image reading device 12. The image data is subjected to image processing according to the image reading device 12 and the writing unit 13, and then converted into optical information by the writing unit 13.

The image forming engine 14 uniformly charges the photoconductor drum 19 with a charging device, and exposes the photoconductor drum 19 with the laser beam emitted by the writing unit 13. The electrostatic latent image on the photoconductor drum 19 is developed by the developing device 18 to become a toner image. The paper feed unit 15 feeds the paper to the transport path 22, and the transport path 22 transports the paper to the photoconductor drum 19. The toner image of the photoconductor drum 19 is transferred to the paper by the secondary transfer voltage, and the toner image is formed on the paper. The paper is conveyed to the fixing device 16 by the conveying belt 23, and the toner image is fixed to the paper by the fixing device 16 and discharged.

The configuration shown in the figure is only an example. Further, the image forming apparatus does not have to be a multifunction device, and may have a printer function. Therefore, for example, the image forming apparatus may be called a printer, a copying machine, a facsimile apparatus, or the like.

<Hardware configuration>
FIG. 3 is an example of a hardware configuration diagram of the image forming apparatus 10. FIG. 3 shows a control unit 30, an operation panel 20, and a paper feeding unit 50 as the main configurations of the image forming apparatus 10 in the present embodiment.

The control unit 30 has a CPU 41, a memory 42, and a network I / F 43, each of which is connected to the bus B. The CPU 41 executes a program stored in the memory 42 to control the entire control unit 30. As for the memory 42, the SSD (Solid State Drive) is a non-volatile memory such as an HDD (Hard Disk Drive) or a volatile memory such as a DRAM. In either case, the program is stored in the memory 42. Further, the memory 42 stores information input to the image forming apparatus 10, information held in advance by the image forming apparatus 10, and the like.

The network I / F43 is a communication device for communicating with an external device via a network such as LAN or the Internet.

Note that FIG. 3 shows a minimum configuration for convenience of explanation, and the control unit 30 has a general configuration such as a microcomputer or an information processing device (ROM, interrupt controller, communication device for communicating via a network, etc.). It has an interface with an external device, etc.).

The paper feed unit 50 will be described. The paper feed unit 50 is at least one of the paper feed unit 15 and the manual feed tray 17. The paper feed unit 50 includes a paper set detection sensor 51, a paper size detection sensor 52, a paper thickness detection sensor 21, and a paper transport motor 56. These are connected to the bus B, transmit a detection result to the CPU 41, and receive a control signal from the CPU 41. The paper set detection sensor 51 detects that paper has been loaded in the bypass tray 17 or the paper feed unit 15. The paper set detection sensor 51 may be any sensor as long as it can detect that there is even one sheet of paper. For example, a weight sensor that turns on the switch by the weight of one sheet of paper, a sensor that detects a paper set based on the presence or absence of light reflection, and the like are used, but the present invention is not limited to this.

The paper size detection sensor 52 is a sensor that detects the vertical and horizontal dimensions of paper. The mechanism of the paper size detection sensor 52 differs between the manual feed tray 17 and the paper feed unit 15. The paper thickness detection sensor 21 is a sensor that measures the thickness of one sheet of paper. The paper transport motor 56 is a motor for transporting one sheet of paper from the manual feed tray 17 or the paper feed unit 15 to the paper thickness detection mechanism 55.

The paper size detection mechanism 53 is a mechanical mechanism for mounting the paper size detection sensor 52 on the image forming apparatus 10. For example, it refers to a mounting portion of the paper size detection sensor 52 and a mechanism for operating or deforming the paper size detection sensor 52. The paper thickness detection mechanism 55 is a mechanical mechanism for mounting the paper thickness detection sensor 21 on the image forming apparatus 10. For example, it refers to a mechanism for operating or deforming the attachment portion of the paper thickness detection sensor 21 and the paper size detection sensor 52. The paper transport mechanism 57 refers to a mechanical mechanism that is driven by a paper transport motor 56 to transport paper. For example, a clutch that brings the paper feed rollers 17a and 15a and the paper feed rollers 17a and 15a into contact with each other corresponds to this.

<Paper size sensor>
The paper size detection sensor 52 of the paper feed unit 15 will be described with reference to FIG. FIG. 4A is a diagram showing a main configuration of the paper feed unit 15, and FIG. 4B is a diagram showing an example of arrangement of the paper size detection sensor 52.

In the main body case 152, a pair of side fences 154a and 154b are arranged so as to face each other in the width direction of the main body case 152. The side fences 154a and 154b have a substantially L-shape for loading paper. Racks 155a and 155b extending in the width direction of the main body case 152 are attached to the side fences 154a and 154b, and the bottom plates 152a of the main body case 152 extend in the moving direction of the side fences 154a and 154b. Guide grooves 156a and 156b are formed for each side fence 154a and 154b. The guide grooves 156a and 156b are formed so as to penetrate the bottom plate 152a of the main body case 152, and the bottom surfaces of the side fences 154a and 154b are guides that enter the guide grooves 156a and 156b and move along them. Pins are attached.

The racks 155a and 155b are meshed with two-stage gears 158 rotatably arranged on the bottom plate 152a of the main body case 152, and the side fences 154a and 154b are provided by the racks 155a and 155b via the two-stage gears 158. In conjunction with this, it moves in the width direction of the main body case 152.

A paper set detection sensor 51 is arranged on at least one of the side fences 154a and 154b. The paper set detection sensor 51 is composed of a mechanical switch that can be pushed down only by placing about one sheet of paper. The detection method of the paper set detection sensor 51 such as optical paper detection is not limited to the mechanical switch.

Gear pulleys 160 and 163 are arranged on the bottom plate 152a of the main body case 152, and wires 164 are engaged with the gear pulleys 160 and 163. Both ends of the wire 164 are attached to guide pins formed on the back surface of the end fence 162 via springs 161a and 161b, respectively.

Further, a slide groove 157 is formed in the main body case 152, and a positioning groove 159 for positioning the end fence 162 for each paper size is formed on the side wall of the slide groove 157. A leaf spring (positioning member) attached to the back surface of the end fence 162 is formed on the side wall of the slide groove 157. When the protruding portion of the leaf spring comes to the position of the positioning groove 159 of the slide groove 157, the protruding portion enters the positioning groove 159 and positions the end fence 162 at an appropriate position for each paper size.

As shown in FIG. 4B, a paper size detection sensor 52 is arranged below the guide groove 156a and the slide groove 157, and the paper size detection sensor 52 presses the paper size detection sensor 52 for each paper size. A sensor element 52b that detects the paper size is attached. Since the paper size detection sensor 52 is formed at a position directly below the guide groove 156a and the slide groove 157, the sensor element 52b of the paper size detection sensor 52 slides with the guide pin of the side fence 154a inserted into the guide groove 156a. Pressed by the guide pin of the end fence 162 inserted into the groove 157, the size of the paper loaded in the paper feed unit 15 is detected.

The illustrated configuration is only an example, and various configurations may be adopted for the configuration of the paper size detection sensor of the paper feed unit 15.

FIG. 5 is an example of a diagram illustrating the paper size detection sensor 52 of the manual feed tray 17. FIG. 5A is an example of a perspective view of the manual feed tray 17, and FIG. 5B is a diagram showing an arrangement example of the paper size detection sensor 52.

The manual feed tray 17 can be housed in the image forming apparatus 10 by being rotated by the user in the direction of the arrow A. When the manual feed tray 17 is in the stored state, the manual feed tray 17 does not protrude significantly from the outer wall surface of the image forming device 10, so that it does not interfere with users around the image forming device 10. On the other hand, when the user sets the paper in the manual feed tray 17 and prints, the user rotates the manual feed tray 17 in the stored state in the direction opposite to the arrow A, as shown in FIG. 5 (a). It will be in a state of use. Then, the user places the paper P to be used on the mounting surface 17c of the manual feed tray 17 in the used state, and sets the paper P on the mounting surface 17c so that the tip of the paper P is positioned at a predetermined position. do.

The manual feed tray 17 of the present embodiment is provided with two side fences 173a and 173b that regulate the positions of both ends in the width direction orthogonal to the transport direction of the paper P placed on the mounting surface 17c. ing. The two side fences 173a and 173b are configured to be slidable in conjunction with each other along the slide groove 176 extending in the paper width direction. Specifically, the two side fences 173a and 173b move in opposite directions by the same distance in synchronization with each other with respect to a predetermined paper width direction reference position set substantially in the center of the mounting surface 17c in the paper width direction. It is configured as follows. Therefore, after the paper P to be used is placed on the mounting surface 17c, the user moves the two side fences 173a and 173b so that they come into contact with both ends in the width direction of the paper P, so that the center position of the paper P in the width direction Can be positioned at a predetermined paper width direction reference position.

Further, the manual feed tray 17 of the present embodiment is provided with a paper length sensor 174 as a sheet length detecting means for detecting the length of the paper P placed on the mounting surface 17c in the transport direction. The paper length sensor 174 is composed of a mechanical switch that can be pushed down only by placing about one sheet of paper. Specifically, it has a protruding portion that protrudes on the mounting surface 17c so as to be able to advance and retreat, and a pressing detection unit that detects whether or not the protruding portion is pushed down below the mounting surface. Thereby, the paper length sensor 174 can detect whether or not the lower surface of the paper P is in contact with or close to a predetermined position on the mounting surface 17c of the manual feed tray 17. Therefore, from the detection result of the paper length sensor 174, it can be determined whether the paper length of the paper P set in the bypass tray 17 is shorter or longer than the position of the protruding portion of the paper length sensor 174. If a plurality of paper length sensors 174 are arranged, the image forming apparatus 10 can determine the paper length in multiple stages.

As shown in FIG. 5B, the manual feed tray 17 has a paper set detection sensor 51 and a paper width sensor 179 in addition to the paper length sensor 174 described above. The paper set detection sensor 51 is provided near the joint portion between the manual feed tray 17 and the main body of the image forming apparatus 10, and when the paper P is set in the manual feed tray 17, the detection signal is output to the CPU 41. Further, the paper width sensor 179 is provided integrally with the side fences 173a and 173b, and outputs the set positions of the side fences 173a and 173b to the control unit 30 as the width of the paper P. The paper width sensor 179 is a distance sensor that measures the distance between the side fences 173a and 173b, and the paper set detection sensor 51 is, for example, a sensor that detects paper by reflecting light. can.

The illustrated configuration is only an example, and various configurations may be adopted for the configuration of the paper size detection sensor of the manual feed tray 17.

<Paper thickness detection sensor>
FIG. 6 is an example of a diagram for explaining the configuration of the paper thickness detection sensor. FIG. 6A shows a schematic side view of the paper thickness detection sensor 21. The paper thickness detection sensor 21 has a displacement amount measurement sensor 211 in which the paper is arranged in a direction perpendicular to the transport path Path, and a metal plate 212. For example, the paper feed roller 17a feeds one sheet of paper to the transport path Path. The lower paper feed roller 17b is fixed, and the upper paper feed roller 17a moves in a direction perpendicular to the paper transport direction. Before the paper passes, the paper feed rollers 17a and 17b are in contact with each other, and when the paper passes, the paper feed rollers 17a move upward by the thickness of the paper.

Further, although the displacement amount measurement sensor 211 is fixed, the metal plate 212 moves together with the paper feed roller 17a. Therefore, the displacement amount measurement sensor 211 can measure the movement amount of the paper feed roller 17a. Since the amount of movement is the same as the thickness of the paper, or at least correlates with the thickness of the paper, the paper thickness measuring unit 31 described later can measure the thickness of the paper. As the measurement principle of the displacement amount measurement sensor 211, it is sufficient that the change in distance can be measured, such as optical distance measurement and distance measurement based on the magnetic flux displacement amount.

When converting the measurement result of the displacement amount measurement sensor 211 into the paper thickness, the change in the environment is taken into consideration as necessary in order to correspond to the change in the surrounding environment (temperature, humidity, etc.).

FIG. 6B is a diagram showing another configuration example of the paper thickness detection sensor 21. The paper thickness detection sensor 21 of FIG. 6B is a contact type sensor. A lever portion 216 that comes into contact with the paper held by a spring 214 or the like is provided on the upper side of the transport path Path. Further, a solenoid 213 is provided above the spring 214, and the solenoid 213 sandwiches the paper sent out via the spring 214 between the lever portion 216 and the stationary portion. The sensor unit 215 measures the thickness of the paper formed between the lever portion 216 pressed when sandwiched and the stationary portion whose position is known. The sensor unit 215 is, for example, a lever-type encoder, a distance measuring sensor, an ultrasonic sensor, or the like.

<About functions>
FIG. 7 is an example of a functional block diagram illustrating the function of the image forming apparatus 10.

<< Functions of the paper feed section >>
The paper feed unit 50 includes a paper set detection unit 51a, a paper size detection unit 52a, a paper thickness detection unit 21a, and a paper transport unit 56a. The paper set detection unit 51a is mainly realized by the paper set detection sensor 51, and detects that paper is set in the bypass tray 17 or the paper feed unit 15.

The paper size detection unit 52a is mainly realized by the paper size detection sensor 52 and the paper size detection mechanism 53, and detects the dimensions of the paper set in the manual feed tray 17 or the paper feed unit 15.

The paper thickness detection unit 21a is mainly realized by the paper thickness detection sensor 21 and the paper thickness detection mechanism 55, and detects the thickness of one sheet of paper set in the bypass tray 17 or the paper feed unit 15.

The paper transport unit 56a is mainly realized by the paper transport motor 56 and the paper transport mechanism 57, and transports the paper set in the manual feed tray 17 or the paper feed unit 15 to the paper thickness detection sensor 21.

<< Functions of the operation panel >>
The operation panel has a display control unit 37 and a paper type input reception unit 38. Each of these functions is a function or means realized by the CPU 41 shown in FIG. 3 executing a program stored in the memory 42 and controlling the operation panel.

The display control unit 37 is realized by the operation panel 20 and the CPU 41 shown in FIG. 3 processing commands and the like, and displays various information on the display of the operation panel 20. For example, the paper type selection screen that accepts the selection of the paper type is displayed.

The paper type input receiving unit 38 is realized by the operation panel 20 and the CPU 41 shown in FIG. 3 processing commands and the like, and accepts the selection of the paper type from the user.

<< Functions of control unit >>
The control unit 30 includes a paper thickness measuring unit 31, a paper thickness determining unit 32, a paper size measuring unit 33, a paper size determining unit 34, and a communication unit 36.

Each of these functions is a function or means realized by the CPU 41 shown in FIG. 3 executing a program stored in the memory 42 to control various hardware. Further, the control unit 30 has a storage unit 35 realized by the memory 42 shown in FIG. A paper size DB (Data Base) 351, a paper thickness DB 352, a conversion formula DB 353, and a type size DB 354 are constructed in the storage unit 35.

表１は、用紙サイズＤＢ３５１に記憶されている用紙サイズテーブルの一例を示す。用紙サイズテーブルには、用紙サイズに対応付けて寸法が登録されている。寸法は、横と縦の長さをミリメートルで表す。なお、この寸法は規格上の値である。また、用紙サイズはＡ３、Ａ４、Ａ５、Ａ６，Ｂ４，Ｂ５、Ｂ６、及び、ハガキや封筒の名称である。ユーザが用紙を縦向きと横向きに設定することができるので、それぞれ縦と横の用紙サイズが登録されている。Ａ３とＢ４で縦しかないのはユーザがＡ３とＢ４を横向きにして画像形成装置１０に設定できないためである。したがって、用紙サイズ検知センサ５２が寸法を測定すると対応する用紙サイズが判明する。

Table 1 shows an example of a paper size table stored in the paper size DB351. Dimensions are registered in the paper size table in association with the paper size. Dimensions represent horizontal and vertical lengths in millimeters. This dimension is a standard value. The paper sizes are A3, A4, A5, A6, B4, B5, B6, and the names of postcards and envelopes. Since the user can set the paper to portrait and landscape, the portrait and landscape paper sizes are registered, respectively. The reason why A3 and B4 are only vertical is that the user cannot set A3 and B4 in landscape orientation on the image forming apparatus 10. Therefore, when the paper size detection sensor 52 measures the dimensions, the corresponding paper size is found.

There are other types of paper sizes other than those shown in Table 1, but they are omitted for convenience of explanation. In addition to Table 1, various standard paper sizes may be registered. In addition, paper sizes of overseas standards such as overseas letter sizes may be included, and paper size tables may be set for each country such as Japan and the United States.

表２は、用紙厚さＤＢ３５２に記憶されている用紙厚さテーブルの一例を示す。用紙厚さテーブルには、用紙厚さ種類に対応付けて坪量が登録されている。坪量は、単位面積当たりの重さをグラムで表す。すなわち、ある坪量の範囲に入る用紙が、予め決まっている用紙厚さ種類に分類される。用紙厚さ種類は、例えば、普通紙１、普通紙２、薄紙、中厚口、厚紙１、厚紙２、厚紙３などである。

Table 2 shows an example of the paper thickness table stored in the paper thickness DB352. In the paper thickness table, the basis weight is registered in association with the paper thickness type. Basis weight expresses the weight per unit area in grams. That is, paper that falls within a certain basis weight range is classified into a predetermined paper thickness type. The types of paper thickness are, for example, plain paper 1, plain paper 2, thin paper, medium-thick mouth, thick paper 1, thick paper 2, thick paper 3, and the like.

Since the image forming apparatus 10 performs the same printing control for a certain basis weight range, the paper thickness type is determined for each basis weight range. The relationship between the basis weight range and the paper thickness type in Table 2 is not fixed and may be changed for reasons such as performing more subdivided printing control. In addition, the type of paper thickness differs depending on the image forming apparatus and the manufacturer of the paper. Therefore, in addition to these, there may be different types of paper thickness.

In addition, each paper thickness type paper does not take only the basis weight range of Table 2, and even one paper thickness type paper may show a basis weight exceeding the basis weight range of Table 2. .. This is because the paper can have various thicknesses.

表３は、変換式ＤＢ３５３に記憶されている変換式テーブルの一例を示す。変換式テーブルには、用紙種類に対応付けて変換式が登録されている。この変換式について詳細は図１１〜１３にて後述するが、厚さと坪量とを対応付ける変換式、又は、厚さから坪量を算出する変換式（この逆でもよい）である。それぞれの用紙種類に１つの変換式が対応付けられている。これは、同じ用紙種類には厚さと坪量に強い相関があるためである。したがって、用紙種類が分かると適切な変換式が定まる。表３の用紙種類は、ユーザが直感的に選択できる用紙種類であり、例えば、ユーザが見た目で判断できる用紙種類になっている。

Table 3 shows an example of the conversion formula table stored in the conversion formula DB353. Conversion formulas are registered in the conversion formula table in association with the paper type. The details of this conversion formula will be described later in FIGS. 11 to 13, but it is a conversion formula that associates the thickness with the basis weight, or a conversion formula that calculates the basis weight from the thickness (or vice versa). One conversion formula is associated with each paper type. This is because there is a strong correlation between thickness and basis weight for the same paper type. Therefore, once the paper type is known, an appropriate conversion formula is determined. The paper types in Table 3 are paper types that can be intuitively selected by the user, and are, for example, paper types that can be visually determined by the user.

Further, in the conversion type table, the presence / absence of paper thickness measurement is registered for each paper type. For the presence / absence of paper thickness measurement, Yes is registered when the image forming apparatus 10 needs to measure the paper thickness, and No is registered when it is not necessary to measure the paper thickness. Further, in the case of No, the paper thickness type is registered. For example, No is registered in the label paper because there is only a paper thickness type of the label paper, which is thick paper 1, even if the paper thickness is not measured. Details will be described later in FIG.

表４は、種類サイズＤＢ３５４に記憶されている種類サイズテーブルの一例を示す。種類サイズテーブルには、用紙種類に対応付けて用紙サイズが登録されている。例えば、普通紙が取り得る用紙サイズはＡ３〜Ｂ６の規格で定まるサイズであり、ハガキが取り得る用紙サイズは郵便ハガキと往復ハガキの規格で定まるサイズである。したがって、ユーザが用紙種類を選択すると、画像形成装置１０は用紙サイズを絞り込むことができる。

Table 4 shows an example of the type size table stored in the type size DB 354. Paper sizes are registered in the type size table in association with the paper type. For example, the paper size that can be taken by plain paper is the size determined by the standards of A3 to B6, and the paper size that can be taken by postcards is the size determined by the standards of postcards and reciprocating postcards. Therefore, when the user selects the paper type, the image forming apparatus 10 can narrow down the paper size.

Note that Table 4 is simplified, and the paper size of each paper type is not limited to those listed in Table 4. For example, envelopes can take a variety of paper sizes.

<< Functions of control unit 30 >>
Subsequently, the function of the control unit 30 will be described. The paper thickness measuring unit 31 is realized by the CPU 41 shown in FIG. 3 processing an instruction or the like, and measures the basis weight by applying the above conversion formula to the paper thickness input by the paper thickness detecting unit 21a. .. When the paper thickness measuring unit 31 measures the basis weight, some calculation or calculation may be included.

The paper size measuring unit 33 is realized by the CPU 41 shown in FIG. 3 processing a command or the like, and measures the paper size based on the paper size dimension input by the paper size detecting unit 52a. When the paper size measuring unit 33 measures the paper size, some calculation or calculation may be included.

The paper thickness determining unit 32 is realized by processing commands by the CPU 41 shown in FIG. 3, and is based on the paper type received by the paper type input receiving unit 38 and the basis weight measured by the paper thickness measuring unit 31. Determine the paper thickness type based on this.

The paper size determination unit 34 is realized by processing commands by the CPU 41 shown in FIG. 3, and has a paper type received by the paper type input reception unit 38 and a paper size size measured by the paper size measurement unit 33. Determine the paper size based on.

The communication unit 36 is realized by the CPU 41 shown in FIG. 3 processing instructions and the network I / F43 or the like, and communicates with an external device. Specifically, the paper type and paper thickness selected by the user are transmitted to an external device, and the paper settings are acquired from the external device.

<Operation procedure>
FIG. 8 is an example of a flow chart showing a flow until the paper setting is determined. Note that the flow chart in FIG. 8 flows from right to left. In FIG. 8, there are three major phases. Phase F1 is an opportunity for the user to select a paper type and a flow until the paper type is determined. Phase F2 is a flow from when the paper size is detected to when the paper size is determined. Phase F3 is a flow from when the paper thickness is detected to when the paper thickness is determined.

<< Phase F1 >>
S1-1: The image forming apparatus 10 is operating in, for example, an energy saving mode. Further, when the image forming apparatus 10 is not in the energy saving mode, the image forming apparatus 10 may simply be on standby or printing.

S2-1: For example, the user sets the paper in the paper feed unit 15 or the bypass tray 17. The paper set detection unit 51a detects a set of paper.

S1-2: Further, the user may open and close the paper feed unit 15. In addition, the user may press the paper tray selection button. The paper feed tray selection button is a button for the user to select the paper feed unit 15 and the manual feed tray 17 displayed on the operation panel 20. In addition to steps S1-1 and S1-2, the process may start at the timing when the user is recognized to print.

S2-3: The paper set detection unit 51a accepts the selection of the opened / closed paper feed unit 15 or the manual feed tray 17, or the paper feed unit 15 or the manual feed tray 17 selected by the paper feed tray selection button.

S2-2: The user may also press the paper type input button. The paper type input button is a button for displaying the paper type selection screen of FIG. 9, and is displayed on the operation panel 20 or the like.

S3: The display control unit 37 displays the paper type selection screen on the operation panel 20 by the notification from the control unit 30. That is, the control unit 30 detects steps S2-1 to S2-3 and displays the paper type selection screen.

S4: Since the user selects the paper type, the paper type input receiving unit 38 accepts the paper type selected by the user.

<< Phase F2 >>
S11-1: For example, when the paper set detection unit 51a detects a set of paper and the side fence of the paper feed unit 15 or the bypass tray 17 is moved, the detection of the paper size is started.
S11-2: Also, the paper size may be detected at all times. This is because the paper size can be detected while the paper is loaded in the paper feed unit 15 or the bypass tray 17. The paper size detection may be started before or after the paper type is selected. However, the paper size is determined to be a suitable paper size after the paper type is determined.

S12: The paper size detection unit 52a detects the size of the paper placed on the paper feed unit 15 or the bypass tray 17.

S13: The paper size measuring unit 33 measures the vertical and horizontal dimensions of the paper size.

S14: The paper size determination unit 34 refers to the size type table in Table 4 and narrows down to the paper size of the paper type selected by the user. The paper size included in a predetermined range (for example, ± 5 [mm]) from the vertical and horizontal dimensions of the paper size is determined from the paper size table in Table 1.

<< Phase F3 >>
S21: It is the timing when the paper thickness is detected by selecting the paper type, pressing the paper thickness detection button, or starting image formation. The paper thickness detection button is a button for the user to arbitrarily detect the thickness of the paper. In the present embodiment, the control unit 30 receives the opportunity to transport the paper, transports the paper, and then detects the paper thickness. As a result, it is possible to measure after making one sheet of paper.

S22: The paper thickness measuring unit 31 controls the paper conveying unit 56a to convey the paper. The mechanism for transporting the paper may be an independent mechanism for detecting the thickness of the paper, or may be used in combination with the transport for printing. As for the paper thickness, the detection may be started before or after the selection of the paper type, as in the case of the paper size. However, the paper thickness is determined to be a suitable thickness after the paper type is determined.

S23: The paper thickness detecting unit 21a measures the paper thickness as shown in FIG.

S24: The paper thickness measuring unit 31 measures the paper thickness using the detection result of the paper thickness detecting unit 21a.

S25: The paper thickness determination unit 32 refers to the conversion formula in Table 3 and reads out the conversion formula of the paper type selected by the user. The paper thickness is converted to the basis weight by the conversion formula, and the paper thickness type to which the basis weight is applied is determined from the reference to the paper thickness table in Table 2.

S30: Since the paper size and the paper thickness type have been determined in the above, the control unit 30 sets these in the image forming apparatus 10 as the final paper setting.

<Paper type selection screen>
FIG. 9 is a diagram showing an example of a paper type selection screen. The paper type selection screen 501 has a message 502 "Please select the type of paper to be printed" and a list 503 of paper types. The radio button 504 is displayed in the paper type list, and the user selects the radio button 504 with a finger or the like. The paper type input receiving unit 38 accepts the paper type based on the selected radio button 504. The paper type displayed on the paper type selection screen 501 is, for example, the paper type shown in Table 4, and is a paper type that the user can visually judge from the appearance of the paper such as shape, gloss, and color. Paper types that cannot be determined without detailed paper size measurement and paper thickness measurement are not displayed.

The displayed paper type is an example, and colored paper or the like may be displayed. However, colored paper is treated in the same way as plain paper. When all the paper types cannot be displayed on the operation panel 20, the frequently used paper types are preferentially displayed. Paper types that cannot be displayed are displayed on a separate page. Since the frequency of use of the paper type differs depending on the user, it is preferable to change the paper type displayed by the display control unit 37 depending on the user. For example, a user is identified by logging in. The display control unit 37 statistically determines the types of paper that the user frequently uses, and displays the most frequently used paper types on the operation panel 20 in order.

Further, since the paper type used in each country is different and the frequency of use is also different, the display control unit 37 displays the paper type used in each country on the operation panel 20 with priority given to the paper type used most frequently. It is preferable to let it. In this case, the user sets the country in which the image forming apparatus 10 is used (or may determine by position information such as GPS), and the display control unit 37 displays the paper type associated with the country.

Further, although it has been explained that the paper type selection screen of FIG. 9 is displayed on the operation panel 20, it may be displayed on the display of a PC (Personal Computer) connected to the image forming apparatus 10 via a network. Even if the setting screen is displayed on the PC, the control unit 30 can similarly determine the paper size and the paper thickness type.

<Determining paper size and paper thickness type>
FIG. 10A is an example of a diagram schematically illustrating determination of paper size and paper thickness.
S1: First, the user selects a paper type on the paper type selection screen 501. Here, it is assumed that plain paper is selected.
S2: According to the type size table in Table 4, the paper size of plain paper is any of A3 to B6.
S3: The dimensions of the paper measured by the paper thickness measuring unit 31 are 104 ± 5 [mm] in the main scanning direction (vertical) and 220 [mm] or less in the sub-scanning direction (horizontal).
S4: The paper thickness determining unit 32 determines a paper size having a width of 220 [mm] or less and a length of 104 ± 5 [mm] from the paper size table in Table 1. Among the A3 to A6 paper sizes, the one that fits this dimension is A6 portrait.

In this way, the paper size can be narrowed down by the user selecting the paper type. Since the paper size is narrowed down by selecting the paper type that can be intuitively determined by the user, it is possible to set the paper size that is difficult for the user to understand with high accuracy only by the simple paper size detection sensor 52.

S5: Next, since the paper type is plain paper, the paper thickness determination unit 32 reads out the conversion formula 1 associated with the plain paper in Table 3.
S6: The paper thickness measuring unit 31 measures the paper thickness. For example, assume that the measured paper thickness is 148 [μm].
S7: The paper thickness determining unit 32 substitutes the paper thickness 148 [μm] into the conversion formula 1 and converts it into the basis weight. For example, 148 [g / m ² ].
S8: The paper thickness determining unit 32 determines the type of paper thickness having a basis weight of 148 [g / m ² ] with reference to the paper thickness table in Table 2. Therefore, cardboard 1 is selected.

In this way, by selecting the paper type by the user, even if papers having similar paper sizes exist, it becomes easy to determine the paper size based on the measurement result of the paper size. For example, the vertical size of A6 (105 mm x 148 mm) and the vertical size of postcards (100 mm x 148 mm) are only 5 mm vertically. It suffices if the paper size detecting unit 52a can measure 100 [mm] and 105 [mm] separately, but about 5 [mm] is included in the error range. This is due to the detection error originally possessed by the paper size detection unit 52a, the variation of the paper when the user sets the paper in the paper feed unit 15 or the manual feed tray 17, and the like.

On the other hand, in the present embodiment, since the plain paper and the postcard are distinguished by the user selecting the paper type, the plain paper is selected even if the detection error of the paper size is ± 5 [mm]. In that case, it can be determined as A6.

The same applies to the paper thickness. The image forming apparatus 10 uses the basis weight [g / m2] as an index of the paper thickness. However, it is difficult to accurately measure the basis weight in the image forming apparatus 10, and expensive sensing is required. Therefore, in the present embodiment, information different from the basis weight (paper thickness, transmitted light amount, etc.) is detected and converted into the basis weight on the image forming apparatus 10 side, but the paper thickness different from the basis weight is used. Since it is detected, the basis weight may not be accurate.

For example, there can be plain and coated paper of the same thickness. When the thickness of plain paper is 128 [um], the basis weight that can be obtained is 130 to 150 [g / m2], and when the thickness of coated paper is 128 [um], the basis weight that can be obtained is 140 to 180 [g / m2]. ], The range of basis weight is different even if the thickness is the same. Therefore, even if the thickness is measured and converted into the basis weight, the width is 130 to 180 [g / m2]. Since 130 to 180 [g / m2] include thick paper 1 to thick paper 2 in the paper thickness type, the paper thickness type cannot be uniquely determined even if the thickness is simply converted to the basis weight.

On the other hand, in the present embodiment, the relationship between the basis weight and the paper thickness can be narrowed down by the user selecting the paper type. For example, if the paper type is limited to plain paper, it is possible to determine that the paper thickness type is thick paper 1.

When the image forming apparatus 10 cannot narrow down the paper size and the paper thickness type to one, the candidates can be displayed and selected by the user. For example, in the case of envelopes, both Western-style No. 3 and long-shaped No. 3 have dimensions of 120 [mm] x 235 [mm], so the paper size cannot be determined from the paper dimensions. As for the paper thickness type, when the thickness is measured as 100 [um], both the medium-thick mouth and the thick paper 1 may exist depending on the paper type, so that the image forming apparatus 10 cannot determine the paper thickness type. .. In such a case, the candidate paper size and paper thickness type are displayed and the user's selection is accepted. The image forming apparatus 10 may select one from a plurality of candidates based on, for example, priority information preset by the user. Further, by displaying the paper size and the paper thickness type selected by the image forming apparatus 10 to the user, it may be confirmed to the user whether or not there is an error in the selection result.

FIG. 10B is an example of a diagram illustrating determination of the paper size and the paper thickness when the paper type is not selected. FIG. 10B is a comparative example with respect to this embodiment.
S1: In FIG. 10B, the paper type is not selected.
S2: Therefore, all the paper sizes that can be printed by the image forming apparatus 10 are candidates for the paper setting.
S3, S4: Therefore, the paper size determination unit 34 determines the A6 length and the postcard length as the paper size of 220 [mm] or less in width and 104 ± 5 [mm] in height. That is, the paper size cannot be narrowed down sufficiently.

S5: Further, since the paper type is not selected, the paper thickness determining unit 32 has no choice but to use all the conversion formulas (the conversion formula of the paper type capable of taking the measured thickness of 148 [μm]). ..
S6, S7: Therefore, the basis weight having a width of 100 to 200 [g / m2] is determined from the thickness of 148 [μm].
S8: As a result, there are three types of paper thickness: medium-thick mouth, thick paper 1, and thick paper 2, and the paper thickness types cannot be sufficiently narrowed down.

As described above, in the image forming apparatus 10 of the present embodiment, since the user selects the paper type, it becomes easy to narrow down the paper size and the paper thickness.

<About conversion formula>
The conversion formula will be described with reference to FIGS. 11 to 13. FIG. 11 is a diagram showing the relationship between the paper thickness and the basis weight of each paper type. As shown in FIG. 11, there is a characteristic relationship between the paper thickness and the basis weight for each paper type. For example, the paper thickness and basis weight of paper type A have a relationship that can be approximated by a straight line A, the paper thickness and basis weight of paper type B have a relationship that can be approximated by a straight line B, and the paper thickness of paper type C. There is a relationship between and basis weight that can be approximated by a straight line C. For example, since the paper type A is plain paper, the paper type B is coated paper, and the paper type C is label paper, the relationship between the paper thickness and the basis weight is different for each paper type.

If the paper thickness determining unit 32 tries to determine the paper thickness type only by the paper thickness, for example, since there are three paper types A to C in 150 [μm], the paper thickness is tsubo. The range of tsubo that can be taken when converted to quantity becomes wider. Therefore, when the paper type is not selected, even if the paper thickness measuring unit 31 measures the paper thickness, the image forming apparatus 10 cannot automatically convert the paper thickness type into the basis weight to determine the paper thickness type.

On the other hand, when the user selects the paper type C, the paper thickness type is unique because the basis weight is almost uniquely determined even if the paper thickness is converted into the basis weight if the same paper type is used. Can be decided. The reason why it is almost unique is that even if it is uniquely determined by the conversion formula, an error is included when the relationship between the thickness and the basis weight is linearly approximated by the regression line.

Not only the paper types A to C, but also other paper types have a strong correlation between the paper thickness and the basis weight. Therefore, if the person in charge of the manufacturer measures the relationship between the paper thickness and the basis weight for the same paper type and linearly approximates it by the least squares method or the like, a conversion formula can be created for each paper type.
Basis weight = α x paper thickness + β
α is the slope of a line and β is the Y intercept. The conversion formula from the paper thickness to the basis weight may be used or a table may be used.

Therefore, if the user selects a paper type that can be intuitively determined, the image forming apparatus 10 can determine the paper thickness (basis weight) that is difficult for the user to set. The image forming apparatus 10 only needs to have a simple paper thickness detection sensor 21, and the cost of the image forming apparatus 10 is unlikely to increase.

FIG. 12 is an example of a diagram for explaining the relationship between the paper thickness and the basis weight of the paper whose paper thickness type is determined by the paper type. Depending on the paper type, such as the paper type C, the paper thickness type may be determined when the paper type is determined. The paper type C in FIG. 12 has a certain range of paper thicknesses, but all the measurement points are included in one paper thickness type (range of basis weight). One paper thickness type (range of basis weight) is a range of basis weight determined for each paper thickness type, for example, as in the paper thickness table in Table 2. The range 550 of FIG. 12 includes a range of about 128 to 169 [g / m ² ], which is a range of basis weight of the paper type C. This is almost the same as the range of basis weight of the paper thickness type of the thick paper 1.

When the user selects the paper type C, the same paper thickness type (thick paper 1) is always determined even if the paper thickness is measured and converted into the basis weight. Therefore, it is not necessary to measure the paper thickness depending on the paper type selected by the user. Therefore, the paper thickness measuring unit 31 of the present embodiment does not measure the paper thickness when a predetermined paper type is selected.

As a result, depending on the paper type selected by the user, it is not necessary to pull in the paper in order to measure the paper thickness, and it is possible to shorten the time from the start to the completion of the paper setting.

On the contrary, if the paper thickness setting is not determined even if the paper type is selected, the paper thickness measuring unit 31 detects the paper thickness and determines the basis weight from the paper thickness according to the paper type. The paper thickness setting is determined by converting to.

Whether or not to measure the paper thickness is determined in advance depending on the paper type. In the present embodiment, as shown in Table 3, the conversion formula DB353 is set, but it may have a DB in which whether or not to measure the paper thickness is independently registered.

FIG. 13 is an example of a diagram for explaining the correlation coefficient of the conversion formula. In the present embodiment, the paper thickness is converted into the basis weight by the conversion formula, and the paper thickness type is determined by the basis weight. Therefore, in order to determine the paper thickness type with higher accuracy, the paper thickness and the basis weight are determined. The higher the conversion accuracy to, the more preferable.

When the person in charge of the manufacturer of the image forming apparatus 10 linearly approximates the relationship between the paper thickness and the basis weight of various paper types without selecting any paper type, the correlation coefficient R between the paper thickness and the basis weight becomes 0.7 or less. It may become. The correlation coefficient R is defined by the following equation.
R = Sxy / √ (SxxSyy)
Sxx is the dispersion of the x component (basis weight), Syy is the dispersion of the y component (paper thickness), Sxy is the product of the average of the x component and the difference between each x component, and the average of the y component and the difference between each y component. Is the sum of the number of measurement points. R has a range of -1 to 1, and the closer it is to 1, the stronger the positive correlation, and the closer it is to -1, the stronger the negative correlation.

Generally, when the correlation coefficient R is 0.7 or less, the positive correlation is considered to be low. In this case, the correct paper thickness type may not be determined when the paper thickness is converted to the basis weight.

In other words, when the person in charge selects the paper type to be displayed on the paper type selection screen 501, if the paper type has a correlation coefficient R of 0.7 or more, the correct paper is converted from the paper thickness to the basis weight. The possibility of determining the thickness type increases. Therefore, in the present embodiment, a paper type having a correlation coefficient R between the paper thickness and the basis weight of at least 0.7 or more is displayed on the paper type selection screen 501.

Further, in order to accurately determine the paper thickness type, it is preferable that there is a stronger correlation. For example, it is preferable that there is a correlation with a correlation coefficient R = 0.9 or more. It has been experimentally confirmed that the correlation coefficient R between the paper thickness and the basis weight is 0.9 or more for the paper types having several thicknesses such as coated paper and plain paper. Therefore, when the paper thickness is converted to the basis weight, the paper thickness type can be determined with high accuracy.

In order to determine the paper thickness type with higher accuracy, it is required that the measurement accuracy of the paper thickness is high. However, it may be affected by the vibration of the image forming apparatus 10 generated when measuring the paper thickness or by the operation of the paper thickness detecting mechanism 55. For example, if the paper thickness is measured during the operation of the image forming apparatus 10, the influence of the operation of the paper thickness detecting mechanism 55 appears in the measurement result, and the error becomes large. Therefore, when the paper is pulled in once and the thickness of one sheet is measured, it is preferable to stop the transport of the paper. When the paper thickness is measured, the accuracy of the paper thickness can be improved by stopping the transport of the paper.

In addition, it may not be sufficient to simply stop the paper transfer. This is because the rotation angle (phase) of the roller when the paper thickness detecting mechanism 55 pulls in the paper with the roller and stops it is unknown. The radii of the rollers are almost uniform, but vary at the micron level. That is, the rollers are not perfect circles, and variations in radius cause errors in the measurement results of paper thickness. Therefore, preferably, the paper thickness measuring unit 31 monitors the output of the paper thickness detection sensor 21 while changing the rotation angle of the roller in the absence of paper, and acquires a zero point. This reveals the relationship between the phase and the zero point. When actually measuring the paper thickness, the paper thickness is corrected by the phase.

<Operation procedure>
FIG. 14 is an example of a flowchart showing a procedure in which the image forming apparatus 10 sets the paper. The process of FIG. 14 is started by the user setting the paper, selecting the paper feed unit 15, pressing the paper type input button, or the like.

By these user operations, the display control unit 37 displays the paper type selection screen 501 on the operation panel 20 (S10).

Next, the paper size measuring unit 33 starts measuring the dimensions of the paper (S20). As a result, the size of the paper size is measured by the time the user selects the paper type.

Next, the paper type input receiving unit 38 accepts the selection of the paper type (S30).

The paper size determination unit 34 determines the paper size according to the paper type (S40). That is, the paper size associated with the paper type selected by the user is read out with reference to the type size table in Table 4. Of these paper sizes, a paper size within a predetermined range from the measured dimensions is determined from the paper size table in Table 1. In this case, a plurality of paper sizes may be determined. Further, the paper size closest to the measured size may be determined from the paper size DB351 in Table 1. In this case, the determined paper size is one.

Next, the paper thickness determination unit 32 determines whether or not the paper type selected by the user is a paper type that does not require measurement of the paper thickness (S50). That is, referring to Table 3, it is determined whether or not the presence or absence of the paper thickness measurement of the paper type selected by the user is No.

If the determination in step S50 is Yes, the process proceeds to step S100. In this case, the paper thickness determination unit 32 reads out the paper thickness type associated with the paper type selected by the user in the conversion formula table (S100).

If the determination in step S50 is No, the paper thickness measuring unit 31 of the control unit 30 controls the paper conveying unit 56a to start drawing the paper (S60).

Next, the paper thickness measuring unit 31 reads out the amount of paper drawn from the storage unit 35 (S70). It is assumed that the amount of paper drawn in is predetermined. This is because if the paper comes out on the transport path 22, it may collide with the paper being transported. For example, it is pulled in by a few centimeters. Step S70 may be performed before step S60.

Next, the paper thickness measuring unit 31 stops the paper conveying unit 56a (S80). By stopping, the thickness of the paper can be measured accurately.

The paper thickness measuring unit 31 measures the paper thickness (S90). When the paper bundle is set, the thickness measurement may be performed only on the first sheet.

Next, the paper thickness determining unit 32 determines the paper thickness type (S100). That is, the conversion formula associated with the paper type selected by the user is read from the conversion formula table in Table 3, and the thickness measured in the conversion formula is substituted to convert to the basis weight. Next, the paper thickness type to which the converted basis weight applies is determined by referring to the paper thickness table in Table 2.

The display control unit 37 displays the determined paper setting on the operation panel 20 or the like (S110). That is, the paper size and the paper thickness type are displayed on the operation panel 20, and the user is inquired whether or not to execute printing. The paper setting inquiry screen is shown in FIG.

The operation panel 20 accepts an input as to whether or not the user has input the print execution, and determines whether or not the user has input the print execution (S120).

When the user inputs the print execution, the image forming apparatus 10 starts printing (S130). If the user does not enter a print execution, the process returns to step S10 and begins with the selection of the paper type.

The thickness measurement of the present embodiment is for narrowing down the types of paper, but apart from this, there is a thickness measurement for determining whether or not the thickness of the paper is within the normal range. This is a conventional thickness measurement, and is a measurement for excluding extremely thick paper or thin paper from the printing target. In this case, the image forming apparatus 10 displays an error and stops the transfer. For example, this is to detect the case where a plurality of sheets of paper are overlapped and conveyed, or the case where different types of paper are mixed. In this thickness measurement, unlike the thickness measurement of the present embodiment, the thickness is measured without stopping the paper transfer. Further, the thickness measurement is performed regardless of whether or not the paper thickness is measured in Table 3 is Yes or No. It is also performed for all the second and subsequent sheets when the paper bundle is set. The user can set in the image forming apparatus 10 whether or not to carry out this thickness measurement.

FIG. 15 shows an example of the paper setting inquiry screen. The paper setting inquiry screen 601 has a message 602 "Do you want to print with this paper setting?", A paper size display field 603, a paper thickness type display field 604, a print execution button 605, and a cancel button 606. The user confirms the paper size and the paper thickness type, and presses the print execution button 605 or the cancel button 606.

Paper sizes include irregular size and paper of the same size (Western envelope and long envelope), and the paper size may not always be accurate. In addition, the basis weight may not be accurate because it is a value converted from the thickness of the paper. Therefore, it is preferable to ask the user to confirm what kind of paper setting has been decided. When the print execution button 605 is pressed, printing is executed, and when the cancel button 606 is pressed, printing is not executed. Therefore, the user can execute printing after confirming the paper settings.

The display control unit 37 may display a plurality of paper sizes or display a plurality of paper thickness types. For example, if the paper size determination unit 34 cannot narrow down the paper size to one, the user can select it. In the present embodiment, the paper thickness type can be narrowed down to one, but for example, when a plurality of conversion formulas are associated with one paper type, a plurality of paper thickness types are determined. In such a case, the user can select the paper thickness type.

Further, on the paper setting inquiry screen 601 for example, the paper size display field 603 may pull down some paper sizes so that the user can select an arbitrary paper size. Similarly, the paper thickness type display field 604 may pull down some paper thickness types so that the user can select any paper thickness type. If the paper setting determined by the image forming apparatus 10 is incorrect, the user can easily correct it.

<Control according to paper settings>
FIG. 16 is a diagram illustrating an example of control of the image forming apparatus 10 according to the paper setting. FIG. 16A schematically shows the relationship between the paper thickness type and the transport speed. That is, the image forming apparatus 10 controls the transport speed to decrease stepwise as the basis weight of the paper thickness type increases. Since the large basis weight means that the paper is thick, the heat of the fixing device 16 is difficult to transfer. Therefore, the transport speed is slowed down to facilitate the fixing of the toner on the paper. Further, a large basis weight means that the paper is hard, so that the tip is easily bent. Therefore, the transport speed is slowed down to suppress the deformation of the paper. In addition, the secondary transfer bias voltage and the like may be controlled. Further, FIG. 16B schematically shows the relationship between the paper thickness type and the transport speed. For the same reason, the image forming apparatus 10 controls the fixing temperature in a stepwise increasing manner as the basis weight of the paper thickness type increases.

In the present embodiment, the paper thickness (basis weight) is taken as an example as the sensing amount of the characteristics of the paper that easily affects the printing control, but the smoothness and Young's modulus also affect the control. FIG. 16C schematically shows the relationship between smoothness and fixing temperature. That is, when the smoothness is high, the image forming apparatus 10 controls the fixing temperature in a stepwise downward tendency. High smoothness means that the toner is easily fixed, so that the toner is fixed even if the fixing temperature is lowered. Therefore, energy consumption can be suppressed.

The smoothness is determined by, for example, the type of paper, and coated paper is smoother than plain paper. In addition, Young's modulus is an index of paper bendability, so it can be converted from thickness and basis weight.

Further, the paper size, which is one of the paper settings, is also appropriately controlled according to the paper size. For example, when the paper size is a postcard, a control called borderless printing is performed. This is a control that forms an image on the entire surface of the postcard. On the other hand, in the case of A6 size, which is similar in size to a postcard, control is performed to secure a margin and form an image. In addition, if the paper size is smaller than the predetermined size, the heating area of the fixing device 16 may be narrowed, or if the paper size is larger than the predetermined size, the heating area of the fixing device 16 may be widened. Further, the transport speed and the fixing temperature may be controlled.

In the first embodiment, the paper size and the paper thickness are detected, the paper type is determined by the combination of the paper size and the paper thickness type, and the paper setting corresponding to the paper type is performed. In this embodiment, the image forming apparatus 10 capable of more accurately determining the thickness type of the paper by correcting the detection result of the thickness of the paper will be described.

FIG. 17 is an example of a functional block diagram illustrating the function of the image forming apparatus 10 in this embodiment. Since the components having the same reference numerals in the functional block diagrams of FIGS. 17 and 7 have the same functions, the description of FIG. 17 mainly describes only the main components of the present embodiment. The control unit 30 of this embodiment newly has a control parameter changing unit 39 and a failure detecting unit 40. The control parameter changing unit 39 changes the control parameter based on the paper thickness corrected by the paper thickness determining unit 32. The control parameters are a fixing temperature, a linear velocity, a bias voltage, and the like set by the image forming apparatus 10 at the time of image forming. The specific value of the control parameter is determined by the paper thickness (paper type). The failure detection unit 40 detects a failure of the paper thickness detection sensor 21. Details will be described later.

The paper thickness determining unit 32 of this embodiment has a function of correcting the paper thickness in addition to the function described in the first embodiment. Correcting the paper thickness means measuring the paper thickness with higher accuracy in consideration of the eccentricity of the rollers as described below.

FIG. 18 is an example of a diagram schematically showing a method of correcting the paper thickness. FIG. 18 shows the amount of paper drawn into the paper thickness detection sensor 21 and the thickness of the detected paper. Black circles indicate measurement points. FIG. 18A shows a case where the roller rotates for one round with paper, and FIG. 18B shows a case where the roller cannot rotate for one round with paper.

First, the fact that the thickness of the paper fluctuates without the paper is due to the eccentric component of the roller. However, the eccentric component due to the rotation of one round of the roller is constant, and the paper thickness detection sensor 21 can identify the eccentric component if the roller rotates one round. As shown in FIG. 18A, in the state with paper, the measured value of the paper thickness detection sensor 21 shifts by the thickness of the paper, but the eccentric component is the same as in the state without paper.

In this way, when the paper thickness is detected by the displacement of the rollers, the paper thickness determining unit 32 removes (cancels) the eccentric component for one round of the rollers, so that the accuracy of the paper thickness is improved. Specifically, the paper thickness determining unit 32 measures the eccentric component without the paper, and further measures the eccentric component with the paper. The difference between the minimum value without paper and the minimum value with paper, the difference between the maximum value without paper and the maximum value with paper, the median value between the minimum value and the maximum value without paper. The difference between (or average) and the median (or average) of the minimum and maximum values with paper is the more accurate paper thickness. That is, the corrected paper thickness.

Further, the change from the state without paper to the state with paper is determined by the change in the paper thickness detected by the paper thickness detection sensor 21 by the threshold value or more. Since the time for the roller to rotate for one round is fixed, the paper thickness detection sensor 21 can determine whether or not the roller has rotated for one round.

However, when the paper is fed from the bypass tray 17, if the rollers rotate by one round, the paper conveyed from the paper feed unit 15 and the paper conveyed from the bypass tray 17 may collide with each other. On the other hand, when the paper thickness detecting mechanism 55 stops the paper from the manual feed tray 17 so as not to collide with the paper conveyed from the paper feed unit 15, the roller may not rotate by one round. FIG. 18B shows a state in which the rollers are stopped and therefore do not rotate for one round. As shown in FIG. 18B, if the roller cannot rotate one round in the presence of paper, the paper thickness determining unit 32 cannot remove the eccentric component. The amount of paper drawn is preset in the paper thickness detecting mechanism 55 for each image forming apparatus 10.

Therefore, when the paper thickness detecting mechanism 55 pulls in the paper once, before rotating the roller by one round, the paper thickness detecting mechanism 55 is stopped within a range that does not affect the paper transport from the paper feeding unit 15, and the paper thickness determining unit 32 is this. The thickness of the paper obtained within the range is used as the temporary paper thickness. Based on this temporary paper thickness, the paper thickness type is determined as described in the first embodiment.

Then, after the image formation is started, the paper thickness detection sensor 21 detects the thickness of the paper again. The paper thickness determining unit 32 rotates the roller one round or more to remove the eccentric component of the roller and corrects the paper thickness to an accurate value.

However, if the control unit 30 performs such control, there is an inconvenience that the time from the paper thickness determination unit 32 determining the paper thickness to the start of image formation after the start of image formation is not sufficient. Bring.

FIG. 19 is an example of a diagram for explaining the correction timing of the paper thickness. FIG. 19 shows changes over time in the target temperature of the paper thickness, the actual temperature, and the fixing temperature detected by the paper thickness detection sensor 21.
Time t1: Paper thickness correction is completed Time t2: Paper finishes passing through the rollers of the paper detection sensor.
Time t3: The next paper starts passing through the paper detection sensor At time t1, the correction of the paper thickness is completed, so the correct paper type is confirmed, but at time t1, the image forming apparatus 10 is already forming an image. .. When the image forming apparatus 10 switches the control parameters (conveying speed, fixing temperature, bias voltage, etc.) during image forming, the image quality is deteriorated due to uneven density and the like. Therefore, the image forming apparatus 10 does not change the control parameter at the time t1 when the image is formed on the paper, but changes the control parameter between the image forming and the image forming or before the start of the image forming. In FIG. 19, since the image formation is completed at the time t2, the control parameter changing unit 39 changes the target temperature at the time t2.

However, such a change of the control parameter is performed when it is determined that the actual temperature, the linear velocity, or the like can reach the target set value when the next image formation starts. In FIG. 19, time T1 is required from the completion of image formation to the start of image formation on the next sheet. On the other hand, the time required for the fixing temperature to be changed by 10 degrees is less than the time T1. Therefore, the control parameter changing unit 39 can change the target temperature when the image formation is completed at time t2.

FIG. 20 is an example of a flowchart showing a procedure in which the control parameter changing unit 39 changes the control parameter. The procedure of FIG. 20 starts with the start of image formation.

First, the paper thickness determining unit 32 starts correcting the thickness of the paper passing through the paper thickness detection sensor 21 from the manual feed tray 17 (S10). The thickness of the temporary paper taken in by the paper thickness detecting mechanism 55 has already been measured within a range that does not collide with the paper conveyed from the paper feed unit 15. Therefore, the paper setting is fixed, and the image forming apparatus 10 is controlled by the control parameters according to the paper setting.

Next, when the paper thickness detection mechanism 55 rotates the roller one round to take in the paper, the correction of the paper thickness is completed (S20).

The control parameter changing unit 39 determines whether the change of the control parameter can be completed by the start of the next image formation (S30). The control parameter changing unit 39 holds the time T1 required from the completion of image formation to the start of the next image formation. Further, the time required to change the linear velocity by ΔVc (ΔV is a minute amount of linear velocity), the time required to change the fixing temperature by ΔT (ΔT is a minute amount of fixing temperature), and the bias voltage by ΔVt (ΔVt is a bias). It holds the time required to change (a minute amount of voltage). Since the current linear velocity, fixing temperature, bias voltage, etc., and the linear velocity, fixing temperature, bias voltage, etc. of the next image formation are known, whether or not the control parameters can be changed and completed by the time the next image formation is started. Can be judged.

If the determination in step S30 is No, the control unit 30 does not change the thickness of the paper depending on the result of the correction (S40). In this case, the process returns to step S30, and when the control parameter changing unit 39 determines that the change of the control parameter can be completed by the start of image formation, the control parameter is changed (S50).

By doing so, the image forming apparatus 10 corrects the thickness of the temporary paper by the thickness of the paper measured by rotating the roller of the paper thickness detection sensor 21 for one round, and suppresses the deterioration of the image quality. Control parameters can be changed.

<Another example of judgment of changing control parameters>
Alternatively, if the image quality can be guaranteed, control without changing the paper thickness is also possible.
FIG. 21 is an example of a flowchart showing a procedure in which the control parameter changing unit 39 changes the control parameter. The procedure of FIG. 21 is started by starting printing. The difference from FIG. 20 is that the control parameters are not changed if the image quality can be guaranteed until the printing is completed.

The processing of steps S10 and S20 is the same as that in FIG. Next, the control parameter changing unit 39 determines whether or not the image quality or productivity can be guaranteed with the settings determined at the time of stopping until the printing of the set number of printed sheets is completed (S30). Even if the control parameter change is not in time for the next print, the image quality will deteriorate after a few pages have been printed, so even if the control parameter change is not reflected during the first few pages of the next print. This is because there is almost no effect on the image quality.

Further, the determination in step 30 is made as follows by using Table 5.

表５には、用紙厚さごとに画像品質が保証されるページ数が登録されている（ページ数登録情報の一例）。表５では、実際に使用されている用紙厚さに対し、画像形成の開始前に検知された用紙厚さと画像形成の開始後に補正された用紙厚さが対応付けられている。実際に使用されている用紙厚さと画像形成の開始後に補正された用紙厚さは同じである。

In Table 5, the number of pages whose image quality is guaranteed is registered for each paper thickness (an example of page number registration information). In Table 5, the paper thickness actually used is associated with the paper thickness detected before the start of image formation and the corrected paper thickness after the start of image formation. The paper thickness actually used and the paper thickness corrected after the start of image formation are the same.

For example, if the paper thickness detected before the start of image formation is plain paper and the paper thickness corrected after the start of image formation is thin paper, the number of pages whose image quality is guaranteed by the setting before correction is page A. Is. In Table 5, the number of pages a to be printed set in the image forming apparatus 10 is also displayed (for explanation, the number of pages to be printed a may change depending on the user's setting). Therefore, when A <a (the number of pages to be printed is larger than the number of pages whose image quality is guaranteed by the setting before correction), the control parameter changing unit 39 determines that the control parameter is changed. .. When A ≥ a (the number of pages whose image quality is guaranteed by the setting before correction is equal to or greater than the set number of pages to be printed), the control parameter changing unit 39 is set to print the set number of prints until printing is completed. It can be judged that the image quality or productivity can be guaranteed by the setting determined at the time of stop.

The image quality and productivity determination methods may be the same. This is because productivity is determined after the image quality is ensured, and if the image quality can be guaranteed, the productivity can also be ensured.

If the determination in step S30 is Yes, the control parameter changing unit 39 does not change the control parameter with the measured paper thickness, and continues printing as it is (S40).

If the determination in step S30 is No, the setting determined at the time of stop cannot guarantee either image quality or productivity, so the control parameter changing unit 39 changes the control parameter according to the measured paper thickness (S50).

That is, when the image quality or productivity is not guaranteed, the control parameter is changed, so that the set number of prints can be printed with the guaranteed image quality or productivity.

For example, the process of FIG. 21 is performed before the process of FIG. That is, when No is determined in step S30 of FIG. 21, the control parameter changing unit 39 determines whether the control parameter can be completely changed by the start of the next image formation in step S30 of FIG. On the contrary, when the image quality cannot be guaranteed, it may be determined whether the control parameter can be completely changed by the start of the next image formation.

<Failure judgment of paper thickness detection sensor>
By correcting the paper thickness, the image forming apparatus 10 can detect a failure of the paper thickness detection sensor 21.
As shown in FIG. 17, the control unit 30 newly has a failure detection unit 40. The failure detection unit 40 holds the paper thickness detected by the paper thickness detection sensor 21 before the start of image formation. That is, the eccentric component for one round of the roller of the paper thickness detection sensor 21 is retained. When the eccentric component for one round of the roller detected by the paper thickness detection sensor 21 after the start of image formation is larger than the eccentric component before the start of image formation, it is determined that the paper thickness detection sensor 21 has failed. .. This is because if the paper thickness detection sensor 21 is normal, the size of the eccentric component does not change even if the paper thickness is actually measured.

For example, the eccentric component for one round of the roller before the start of image formation is ± 30μ, and the eccentric component for one round of the roller after the start of image formation measured for correcting the paper thickness is ± 30μ. If it is large, the failure detection unit 40 determines that the paper thickness detection sensor 21 has failed.

FIG. 22 is an example of a flowchart showing a procedure in which the failure detection unit 40 detects a failure of the paper thickness detection sensor 21. The procedure of FIG. 22 starts with the start of printing.

Steps S10 and S20 are the same as in FIG. Next, the failure detection unit 40 determines whether or not the eccentric component after the start of image formation is larger than the eccentric component before the start of image formation (S30). The judgment may be made in consideration of the margin rather than the eccentric component itself after the start of image formation.

If the determination in step S30 is No, the paper thickness is corrected as described with reference to FIGS. 20 and 21 (S60).

If the determination in step S30 is Yes, the failure detection unit 40 determines that the paper thickness detection sensor 21 has failed (S40).

In this case, since the paper thickness cannot be corrected correctly, the control parameter changing unit 39 does not correct the paper thickness (S50). Therefore, the image forming apparatus 10 continues printing with the paper thickness detected before the start of image forming. As a result, printing can be performed with the paper setting determined based on the paper thickness detected by the paper thickness detection sensor 21 before the failure is detected.

Alternatively, it may be estimated that the reliability of the paper thickness before the start of image formation is not high, and the control unit 30 may perform a process of stopping the printing operation. In this case, it is preferable to display an error message on the operation panel 20 indicating that the failure of the paper thickness detection sensor 21 has been detected.

By correcting the paper thickness in this way, it is possible to detect a failure of the paper thickness detection sensor 21 or output a printed matter having deteriorated image quality because the paper thickness is not measured correctly. Can be suppressed.

<Other application examples>
Although the best mode for carrying out the present invention has been described above with reference to examples, the present invention is not limited to these examples, and various modifications are made without departing from the gist of the present invention. And substitutions can be made.

For example, in the present embodiment, the thickness of the paper is converted to the basis weight, which is one of the characteristics of the paper, but it may be converted to the continuous weight. The ream weight means the weight of 1000 sheets of paper. If the paper size is known, the basis weight and ream weight can be converted to each other.

Further, in the present embodiment, the electrophotographic image forming apparatus 10 has been described, but the image forming apparatus 10 may form an image by an inkjet method. In this case, the image forming apparatus 10 controls the ejection speed and the ejection amount of ink droplets according to the type of paper thickness. Further, the ejection speed and the ejection amount of ink droplets may be controlled depending on the paper type. Further, it is possible to control to change the range in which the image is formed, as in borderless printing, depending on the paper size.

Further, the image forming apparatus 10 may form an image by a thermal transfer method. In this case, the image forming apparatus 10 controls the temperature for thermal transfer and controls the paper feed rate according to the type of paper thickness.

Further, in the present embodiment, the image forming apparatus 10 converts the thickness into the basis weight, but the conversion from the thickness to the basis weight may be performed by an external device. The communication unit 36 of the image forming apparatus 10 transmits the measured thickness and the paper type selected by the user to the server connected via the network. The server selects a conversion formula according to the paper type, converts the thickness into a basis weight, and transmits it to the image forming apparatus 10. The type of paper thickness may be transmitted to the image forming apparatus 10 instead of the basis weight. In this way, since the image forming apparatus 10 does not need to have a conversion formula, the configuration and processing of the image forming apparatus 10 can be simplified.

Further, although the conversion formula for associating the paper thickness and the basis weight is represented by a straight line, the paper thickness and the basis weight may be associated with a curve such as a quadratic formula or a cubic formula.

The paper type input receiving unit 38 is an example of the receiving means, the paper thickness measuring unit 31 is an example of the thickness measuring means, the paper thickness determining unit 32 is an example of the setting determining means, and the conversion type DB353 is used. The conversion formula of is an example of conversion information, the paper size measuring unit 33 is an example of the dimension measuring means, and the paper size determining unit 34 is an example of the size determining means. The type size table is an example of type size information, the paper size table is an example of dimensional information, the display control unit 37 is an example of display control means, the operation panel 20 is an example of a display device, and the communication unit 36. Is an example of communication means. The control parameter changing unit 39 is an example of the control changing means, and the failure detecting unit 40 is an example of the failure detecting means.

10 Image forming device 20 Operation panel 21 Paper thickness detection sensor 21a Paper thickness detection unit 30 Control unit 31 Paper thickness measurement unit 32 Paper thickness determination unit 33 Paper size measurement unit 34 Paper size determination unit 35 Storage unit 37 Display control unit 38 Paper type input reception section

JP-A-2015-170895

Claims (18)

An image forming apparatus that forms an image on the sheet material based on the sheet material setting related to the sheet material.
Reception means for accepting selection of sheet material type,
A thickness measuring means for measuring the thickness of the sheet material, and
It has a setting determining means for determining the sheet material setting regarding the thickness of the sheet material based on the sheet material type received by the receiving means and the thickness measured by the thickness measuring means .
The thickness measuring means detects the eccentric component of the roller by rotating the roller once after the measured thickness of the sheet material changes by a threshold value or more, and determines the eccentric component from the thickness of the sheet material. Remove and
An image forming apparatus having a failure detecting means for detecting a failure of the thickness measuring means when the eccentric component measured after the start of image formation is larger than the eccentric component measured before the start of image formation. .. The setting determining means refers to the conversion information in which the conversion information for converting the thickness of the sheet material into the sheet material setting regarding the thickness of the sheet material is associated with the sheet material type.
Claim 1 for converting the thickness measured by the thickness measuring means into the sheet material setting relating to the thickness of the sheet material by using the conversion information associated with the sheet material type received by the receiving means. The image forming apparatus according to. The conversion information is information for converting the thickness of the sheet material into the basis weight for each type of the sheet material.
The setting determining means converts the thickness measured by the thickness measuring means into a basis weight using the conversion information, and determines the sheet material setting regarding the thickness of the sheet material corresponding to the basis weight. Item 2. The image forming apparatus according to item 2. A dimension measuring means for measuring the dimensions of the sheet material, and
A size determining means for determining the sheet material setting regarding the size of the sheet material based on the sheet material type received by the receiving means and the size measured by the dimension measuring means, and a size determining means.
The image forming apparatus according to any one of claims 1 to 3. The size determining means
With reference to the type size information in which the size of the sheet material is associated with the type of the sheet material, the size of the sheet material associated with the type of the sheet material received by the reception means is acquired.
Of the acquired size of the sheet material, the sheet material having the dimension within a predetermined range with respect to the dimension measured by the dimension measuring means by referring to the dimension information in which the size and the dimension of the sheet material are associated with each other. The image forming apparatus according to claim 4, wherein the size is determined by the sheet material setting regarding the size of the sheet material. When the sheet material type received by the receiving means is a predetermined sheet material type,
The thickness measuring means does not measure the thickness of the sheet material,
The setting determining means according to any one of claims 1 to 5, wherein the setting determining means acquires the sheet material setting relating to the thickness of the sheet material which is previously associated with the sheet material type received by the receiving means. Image forming device. The image forming apparatus according to claim 6, wherein the predetermined sheet material type is a sheet material that can take only one sheet material setting regarding the thickness of the sheet material. Since the receiving means receives the selection of the sheet material type, the receiving means has a display control means for displaying a list of the sheet material types on the display device.
Any of claims 1 to 7, wherein the display control means displays the sheet material type that can be determined by the appearance of the shape, color, or gloss, and does not display the sheet material type that cannot be selected without determining the size and thickness. The image forming apparatus according to item 1. The thickness measuring means is arranged in the transport path of the sheet material, and is arranged.
The image forming apparatus according to any one of claims 1 to 8, wherein the thickness measuring means measures the thickness of the sheet material after stopping the sheet material to be conveyed. The fourth aspect of claim 4 in which the sheet material setting regarding the thickness of the sheet material determined by the setting determining means and the sheet material setting regarding the size of the sheet material determined by the size determining means are displayed on a display device. Image forming device. After the thickness measuring means stops the sheet material to be conveyed and measures the thickness of the sheet material,
When the image forming apparatus starts image forming, the thickness measuring means measures the thickness of the conveyed sheet material again in consideration of the error of the thickness measuring means.
It has a control changing means for changing a control parameter of image formation based on the thickness of the sheet material measured in a state where the error is taken into consideration.
The image forming apparatus according to claim 9, wherein an image is formed on the sheet material based on the changed control parameters. When the thickness measuring means measures the thickness of the sheet material after the start of image formation,
The image forming apparatus according to claim 11 , wherein the control changing means does not change the control parameter while the image is formed on the sheet material. When the time required for changing from the current control parameter to the control parameter for the next image formation is longer than the time from the end of the image formation to the start of the next image formation, the control changing means said. The image forming apparatus according to claim 12 , wherein the control parameters are not changed. The control changing means refers to the page number registration information in which the number of pages is registered in association with the sheet material determined before the start of image formation and the sheet material determined after the start of image formation.
When the number of pages registered in the page number registration information is larger than the number of pages forming an image, the control parameter is not changed.
The image forming apparatus according to any one of claims 11 to 13 , wherein when the number of pages to form an image is equal to or greater than the number of pages registered in the number of pages registration information, the control parameter is changed. The image forming apparatus according to claim 1 , wherein when the failure detecting means detects a failure of the thickness measuring means, the image forming is continued with the sheet material setting determined before the start of image forming. An image forming apparatus that forms an image on the sheet material based on the sheet material setting related to the sheet material.
Reception means for accepting selection of sheet material type,
A thickness measuring means for measuring the thickness of the sheet material, and
The sheet material type received by the receiving means and the thickness measured by the thickness measuring means are transmitted to an external device, and the external device adjusts to the sheet material type and the thickness measured by the thickness measuring means. It has a communication means for acquiring the sheet material setting regarding the thickness of the sheet material, which is determined based on the above .
The thickness measuring means detects the eccentric component of the roller by rotating the roller once after the measured thickness of the sheet material changes by a threshold value or more, and determines the eccentric component from the thickness of the sheet material. Remove and
An image forming apparatus having a failure detecting means for detecting a failure of the thickness measuring means when the eccentric component measured after the start of image formation is larger than the eccentric component measured before the start of image formation. .. An image forming apparatus that forms an image on the sheet material based on the sheet material setting related to the sheet material.
Reception means for accepting selection of sheet material type,
A thickness measuring means for measuring the thickness of the sheet material, and
It functions as a setting determining means for determining the sheet material setting regarding the thickness of the sheet material based on the sheet material type received by the receiving means and the thickness measured by the thickness measuring means.
The thickness measuring means detects the eccentric component of the roller by rotating the roller once after the measured thickness of the sheet material changes by a threshold value or more, and determines the eccentric component from the thickness of the sheet material. Remove and
When the eccentric component measured after the start of image formation is larger than the eccentric component measured before the start of image formation, the image forming apparatus further detects a failure of the thickness measuring means. A program to function as a detection means. It is a setting method performed by an image forming apparatus that forms an image on the sheet material based on the sheet material setting related to the sheet material.
The step that the reception means accepts the selection of the sheet material type,
A step in which the thickness measuring means measures the thickness of the sheet material,
A step in which the setting determining means determines the sheet material setting regarding the thickness of the sheet material based on the sheet material type received by the receiving means and the thickness measured by the thickness measuring means.
The thickness measuring means detects the eccentric component of the roller by rotating the roller once after the measured thickness of the sheet material changes by a threshold value or more, and determines the eccentric component from the thickness of the sheet material. Steps to remove and
When the eccentric component measured after the start of image formation is larger than the eccentric component measured before the start of image formation by the failure detecting means, the step of detecting the failure of the thickness measuring means and the step of detecting the failure of the thickness measuring means.
Setting method to have.

Images