JP7596161B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device that forms an image on a sheet.

In an image forming device, a configuration is known in which the type of sheet on which an image is formed is detected by a sensor provided in the device, and printing is performed with recommended settings corresponding to the detected type. In an image forming device, a configuration is also known in which a user selects the type of sheet on which an image is formed, and printing is performed with settings corresponding to the type selected by the user. In a case in which the user can select the type of sheet, a configuration is disclosed in which an image is formed with settings corresponding to the detected type of sheet if the user's selection differs from the detected type of sheet (see Patent Document 1).

JP 2012-181223 A

However, in the image forming device described in Patent Document 1, even if the sheet type selected by the user is a type that can form an image with higher productivity than the detected sheet type, the image is formed with the productivity corresponding to the detected sheet type. For this reason, in the image forming device described in Patent Document 1, there are cases where it is not possible to form an image on a sheet with the productivity desired by the user, and there is a risk that the user's demands cannot be fully met.

The present invention aims to provide an image forming device that can form a good image on a sheet according to the detected type of sheet and can fully meet the needs of users.

The present invention includes an image forming unit that transports a sheet according to a process speed while forming an image on the sheet, a detection means that detects the type of sheet transported to the image forming unit, a reception means that receives information on the type of sheet from a user, and a control unit capable of executing a first mode in which the image forming unit is controlled according to the type of sheet detected by the detection means, and a second mode in which the image forming unit is controlled according to the type of sheet received by the reception means, and is characterized in that the control unit controls the image forming unit in the second mode when the process speed corresponding to the type of sheet received by the reception means is faster than the process speed corresponding to the type of sheet detected by the detection means.

The present invention also includes an image forming unit that transports a sheet according to a process speed while forming an image on the sheet, a detection means that detects the type of sheet transported to the image forming unit, a reception means that receives information on the type of sheet from a user, and a control unit that can set the process speed, and is characterized in that the control unit sets the process speed to the process speed corresponding to the type of sheet received by the reception means when the process speed corresponding to the type of sheet received by the reception means is faster than the process speed corresponding to the type of sheet detected by the detection means.

According to the present invention, it is possible to form a good image on a sheet according to the detected type of sheet, and also to fully meet the needs of the user.

1 is a schematic diagram of an image forming apparatus according to a first embodiment. 1 is a schematic cross-sectional view of a fixing device according to a first embodiment. FIG. 2 is a schematic configuration diagram of a weight detection unit according to the first embodiment. FIG. 2A is a perspective view of a surface property detection unit according to the first embodiment, and FIG. 2B is a cross-sectional view of the surface property detection unit. FIG. 2 is a top view of a surface property detection unit according to the first embodiment. 2 is a control block diagram of the image forming apparatus according to the first embodiment. FIG. FIG. 2 is a control block diagram of the fixing device according to the first embodiment. 5 is a diagram showing conveying speeds and fixing temperatures corresponding to input sheet types according to the first embodiment; FIG. 5 is a diagram showing fixing temperatures corresponding to detected sheet types according to the first embodiment; FIG. 5 is a flowchart showing a control process executed by a CPU according to the first embodiment to determine whether the CPU controls an image forming unit in a first mode or in a second mode. 10 is a flowchart showing a control process executed by a CPU according to a second embodiment to determine whether the CPU controls an image forming unit in a first mode or in a second mode. 13 is a flowchart showing a control process executed by a CPU according to a third embodiment to determine whether the CPU controls an image forming unit in a first mode or in a second mode.

First Embodiment
Hereinafter, embodiments of the present invention will be described in detail with reference to Fig. 1 to Fig. 10. First, a schematic configuration of an image forming apparatus according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a front view of an electrophotographic image forming apparatus 1. Note that the image forming apparatus 1 shown in Fig. 1 is configured to be capable of forming a multi-color image on a sheet, but it may also be an image forming apparatus 1 that forms a monochromatic image.

[Image forming apparatus]
The image forming apparatus 1 of the first embodiment is a tandem type color laser beam printer that outputs a multi-color image by superimposing images of multiple developers of different colors. The developers are, for example, toners of four colors, such as yellow (Y), magenta (M), cyan (C), and black (K). A transfer material cassette 2 stores a sheet S as a transfer material. The sheet S is picked up from the transfer material cassette 2 by a pickup roller 4 and transported by a paper feed roller 5 and a registration roller 6.

The sheet S conveyed by the registration rollers 6 is conveyed to a type detection device 7, which serves as a detection means for detecting the type of the sheet S by detecting the surface roughness and mass per unit area (hereinafter referred to as "weight per unit area") of the sheet S. The type detection device 7 has a weight detection section 30 that detects the weight per unit area of the sheet S, and a surface property detection section 40 that detects the surface roughness as the surface property of the sheet S. Details of the type detection device 7 will be described later.

Then, the sheet S is transported from the type detection device 7 to the image forming unit 100, where an image is formed and fixed. The image forming unit 100 has a transfer unit 10 that transfers an image onto the sheet S, and a fixing device 20 as a fixing unit that fixes the image transferred onto the sheet S.

The transfer unit 10 has a photosensitive drum 11 as an image carrier that carries an electrostatic latent image or a toner image, and a charging roller 12 as a charging unit that uniformly charges the surface of the photosensitive drum 11 to a predetermined potential. The transfer unit 10 also has an exposure device that irradiates the surface of the photosensitive drum 11 with light in response to an image signal to form an electrostatic latent image on the photosensitive drum 11, and a laser scanner 13 as an optical scanning device. The transfer unit 10 also has a process cartridge 14 having a development roller 15 that develops the electrostatic latent image formed on the photosensitive drum 11 with toner to make it visible. The transfer unit 10 also has a primary transfer roller 16 that primarily transfers the toner image formed on the photosensitive drum 11 to an intermediate transfer belt 17 as an intermediate transfer body, and a drive roller 18 that rotates and drives the intermediate transfer belt 17. The transfer unit 10 also has a secondary transfer roller 19 that transfers the toner image formed on the intermediate transfer belt 17 to a sheet S.

In the transfer unit 10, the sheet S is sandwiched in the nip portion N1 formed by sandwiching the intermediate transfer belt 17 between the drive roller 18 and the secondary transfer roller 19, so that the toner image formed on the intermediate transfer belt 17 is transferred to the sheet S. In addition, in the transfer unit 10, the sheet S is sandwiched in the nip portion N1 and transported toward the fixing device 20.

The fixing device 20 applies heat and pressure to the unfixed toner image transferred to the sheet S, melting and fixing the toner image to the sheet S, thereby fixing the image. The sheet S on which the image has been fixed by the fixing device 20 is discharged by a pair of discharge rollers 28 to a discharge tray (not shown).

[Fixing device]
2 is a schematic cross-sectional view of the fixing device 20. The fixing device 20 of the first embodiment is a fixing device of a film heating type. The fixing device 20 is not limited to a film heating type, and may be a fixing device of other configurations such as a heat roller type or an electromagnetic induction heating type. In the following description, the direction perpendicular to the conveying direction of the sheet S is also referred to as the longitudinal direction of the fixing device 20, the direction parallel to the conveying direction of the sheet S is also referred to as the transverse direction of the fixing device 20, the longitudinal dimension of the fixing device 20 is also referred to as the length, and the transverse dimension of the fixing device 20 is also referred to as the width.

The fixing device 20 has a cylindrical fixing film 61 and a pressure roller 63 that is biased toward the fixing film 61. The fixing film 61 is configured by coating a heat-resistant elastic layer of a 300 μm-thick silicone rubber layer on a substrate made of a thin SUS layer having a small heat capacity, heat resistance, and thermoplasticity. The substrate of the fixing film 61 may be made of a resin film such as polyimide or polyamideimide, or a thin metal sleeve. A heat-resistant release layer made of a fluororesin such as PFA, PTFE, or FEP may be formed on the outer peripheral surface of the elastic layer of the fixing film 61.

A guide member 62 is disposed within the fixing film 61, which contacts the inner surface of the fixing film 61 and slides against the inner surface of the fixing film 61 when the fixing film 61 is rotated. The guide member 62 is formed into a gutter shape with a substantially semicircular cross section in the longitudinal direction. The guide member 62 in the first embodiment is molded from PPS (polyphenylene sulfide). Note that the material constituting the guide member 62 is not limited to PPS, and is preferably made of a material with excellent heat insulation properties in order to prevent heat radiation in the opposite direction of the fixing nip portion N2 described later, that is, inward of the fixing film 61. Specifically, the guide member 62 may be made of liquid crystal polymer, phenolic resin, PEEK (polyether ether ketone), etc.

A groove 62a is formed on the underside of the guide member 62, and a heater 60 serving as a heat generating member is supported in the groove 62a. The heater 60 has a heater substrate 60a extending in the longitudinal direction, an electrically-applied heat generating resistor 60b serving as a heat generating member arranged along the longitudinal direction of the heater substrate 60a, and a protective glass layer 60c covering the electrically-applied heat generating resistor 60b. In addition, a temperature detection member 64 serving as a temperature sensor for detecting the temperature of the heater 60 is arranged near the heater 60 at a position that overlaps in the vertical direction with the area (paper passing area) through which the sheet S passes when the sheet S passes through the fixing nip portion N2.

The heater substrate 60a of the first embodiment is a thin plate heater substrate made of Al ₂ O _3. The heater substrate 60a may be made of AlN.

The heat generating resistor 60b is disposed on the surface of the heater substrate 60a by forming a pattern of a heat generating resistor paste mainly composed of Ag/Pd by screen printing or the like. The heat generating resistor 60b constitutes an electric circuit (not shown) together with a power supply electrode pattern (not shown) formed integrally with the heat generating resistor 60b on the inside of both longitudinal ends of the heater substrate 60a. The heat generating resistor 60b generates heat when electricity is applied from a power supply control circuit (not shown) via the power supply electrode pattern.

The protective glass layer 60c is a glass coating layer that is applied to the heat generating resistor 60b to ensure the wear resistance of the heat generating resistor 60b against the fixing film 61. The heater 60 is supported by the guide member 62 so that the protective glass layer 60c faces the fixing film 61.

The pressure roller 63 is disposed below and parallel to the fixing film 61, and has a multi-layer structure in which an elastic layer 63b is provided on a metal core 63a, and a release layer 63c is provided on the elastic layer 63b.

The core metal 63a is made of sulfur and sulfur composite free-cutting steel material (SUM). Metal materials such as stainless steel (SUS) and aluminum can be used for the core metal 63a. The elastic layer 63b is made of silicone rubber. Silicone-based solid rubber, sponge rubber, elastic foam rubber, or the like can be used for the elastic layer 63b. The release layer 63c is made of a PFA tube. A fluororesin material can be used for the release layer 63c.

The pressure roller 63 is rotatably supported by the frame (not shown) of the fixing device 20 via bearings (not shown) at both longitudinal ends of the core 63a. The bearings at both longitudinal ends of the pressure roller 63, which rotatably support the core 63a, are biased toward the fixing film 61 with a predetermined pressure by a pressure mechanism (not shown). As a result, in the fixing device 20, a fixing nip portion N2 of a predetermined width is formed between the heater 60 and the pressure roller 63, with the fixing film 61 sandwiched between them. In the fixing device 20, a sheet S carrying an unfixed toner image is passed (introduced) into the fixing nip portion N2, and the image is fixed to the sheet S by heating and pressing it.

The pressure roller 63 is driven to rotate by the power of the fixing motor M1 being transmitted to the core metal 63a which is drivingly connected to the pressure roller 63 via a gear or belt, and the fixing film 61 is driven to rotate by the pressure roller 63. Therefore, the pressure roller 63 also functions as a backup member when the sheet S is being transported.

The temperature detection member 64 has a temperature detection element such as a semiconductor whose resistance value changes with temperature, and is configured to be able to detect the temperature of the heater 60 by monitoring the change in resistance value using an electric circuit (not shown). In addition, the temperature detection member 64 is arranged in a position that overlaps with the paper passing area in the vertical direction, so that the temperature of the heater 60 can be detected so that the temperature of the heater 60 is at a temperature that provides good fixing properties even when a sheet S of the maximum width on which an image can be formed is passed through the fixing nip portion N2.

[Type detection device]
The image forming apparatus 1 of the first embodiment includes, as a type detection device 7, a weight detection section 30 that detects the weight per unit area of the sheet S, and a surface property detection section 40 that detects the surface roughness of the sheet S. As shown in Fig. 1, in the image forming apparatus 1, the weight detection section 30 is disposed downstream of the surface property detection section 40 in the conveying direction of the sheet S. Note that the weight detection section 30 and the surface property detection section 40 may be disposed such that the weight detection section 30 is disposed upstream of the surface property detection section 40 in the conveying direction.

[Weight detection section]
3 is a schematic diagram of the weight detection unit 30. In the weight detection unit 30 of the first embodiment, a transmission unit 31 and a reception unit 32 are arranged facing each other so as to sandwich the conveyance path of the sheet S. The transmission unit 31 and the reception unit 32 are each composed of a piezoelectric element (piezo element) which is an element for converting mechanical displacement into an electric signal and an electrode terminal. In the weight detection unit 30 of the first embodiment, ultrasonic waves having a frequency characteristic of 32 kHz are transmitted and received by the transmission unit 31 and the reception unit 32. Here, the frequency of the ultrasonic waves transmitted and received by the transmission unit 31 and the reception unit 32 is set in advance, and it is sufficient that the frequency is selected in an appropriate range depending on the configuration of the transmission unit 31 and the reception unit 32, the detection accuracy, and the like.

In the weight detection unit 30, a pulse voltage of a predetermined frequency is input to the electrode terminal of the transmission unit 31, causing the piezoelectric element to oscillate and generate ultrasonic waves. The generated ultrasonic waves propagate through the air and reach the sheet S, causing the sheet S to vibrate. As the sheet S vibrates, in the weight detection unit 30, the ultrasonic waves generated by the transmission unit 31 propagate through the sheet S to the reception unit 32. The reception unit 32 outputs a voltage from the piezoelectric element according to the amplitude of the received ultrasonic waves, and the weight per unit area of the sheet S is determined by the CPU 22 (see FIG. 6) based on the output voltage.

In the weight detection unit 30, when the sheet S passes between the transmission unit 31 and the reception unit 32, ultrasonic waves are emitted from the transmission unit 31 and received by the reception unit 32. The ultrasonic data received by the reception unit 32 is sent to the sheet determination processing unit 26 (see FIG. 6) via the engine I/F unit 27 (see FIG. 6), and is converted into data on weight per unit area (g/ ^m2 ) according to instructions from the CPU 22 (see FIG. 6).

[Surface property detection unit]
Fig. 4(a) is a perspective view of the surface property detection unit 40, and Fig. 4(b) is a cross-sectional view of the surface property detection unit 40. The surface property detection unit 40 has an LED 41 that irradiates light onto the surface of the sheet S, an imaging lens 42 that forms an image of a reflected component of the light irradiated by the LED onto the sheet S, and a CMOS line sensor 43 that captures the light imaged by the imaging lens 42. The surface property detection unit 40 also has a protective member 47 that protects the LED 41 and the imaging lens 42, and inner surface reference plates 46a and 46b that have a uniform reflectance and are disposed on both ends of the area where the LED 41 can irradiate light.

The LED 41 emits light at an angle of approximately 10° to the surface of the sheet S, generating light and dark areas according to the surface roughness of the sheet S. In the surface property detection unit 40, the light and dark areas (shadows) according to the surface roughness of the sheet S are imaged by the imaging lens 42 and captured by the CMOS line sensor 43.

As shown in FIG. 4B, the imaging lens 42 and the CMOS line sensor 43 are disposed in a direction perpendicular to the conveying direction of the sheet S. This allows the surface property detection unit 40 to simultaneously capture the reflected light from the surface of the sheet S and the reflected light from the inner surface reference plates 46a and 46b using the light emitted from the LED 41.

Figure 5 is a top view of the surface property detection unit 40. As shown in Figure 5, the surface property detection unit 40 has an effective sheet image range W1 that is centered on the optical axis center OC of the LED 41 and detects reflected light used to determine the surface roughness of the sheet S. In addition, the surface property detection unit 40 has inner surface reference plate effective image ranges W2 and W3 at both ends of the area where the LED 41 can irradiate light, which detect reflected light from the inner surface reference plates 46a and 46b.

In the surface property detection unit 40, light is emitted from the LED 41 through the engine I/F unit 27 (see FIG. 6) when the conveyed sheet S faces the imaging lens 42 and the CMOS line sensor 43. The CMOS line sensor 43 captures an image of the reflected light reflected from the surface of the sheet S, and sends the captured reflected light data of the sheet S to the sheet determination processing unit 26 (see FIG. 6) of the CPU 22 through the engine I/F unit. The CPU 22 (see FIG. 6) determines the surface property of the sheet S from the reflected light data sent to the sheet determination processing unit 26.

[Control Block]
6 is a control block diagram of the image forming apparatus 1 of the first embodiment. The host computer HC is connected to a printer controller 21 that controls the operation of the image forming apparatus 1 by a communication line, and transmits image data to a CPU 22 of the printer controller 21 via a host I/F unit 23. The CPU 22 as a control unit processes image data received from the host computer HC via the host I/F unit 23 in an image processing unit 24, and transmits the image data to an image forming engine unit 50 via an engine I/F unit 27. The image forming engine unit 50 includes a fixing device 20 and a type detection device 7.

The printer controller 21 also receives print settings for the sheet S input by the user from a print input unit 70 (see FIG. 1) provided on the top of the image forming device 1 via the print input unit I/F unit 25. The print input unit 70 is configured to be able to input the type of sheet S contained in the transfer material cassette 2 as a print setting. This print input unit 70 constitutes a receiving means for receiving sheet information from the user in the first embodiment.

The CPU 22 controls the image forming unit 100 using information related to the type of sheet S input from the print input unit 70 and information on the sheet S determined by the type detection device 7. Specifically, the CPU 22 is configured to be able to set the conveying speed (process speed) of the sheet S and the temperature (fixing temperature) of the heater 60 in the fixing device 20. The control of the image forming unit 100 by the CPU 22 will be described later.

[Control block of fixing device]
7 is a control block diagram of the fixing device 20. The fixing control unit 65 controls the rotation speed of the pressure roller 63 (see FIG. 2) and the fixing temperature of the heater 60 based on a print signal (image formation signal) received from the CPU 22 via the engine I/F unit 27 (see FIG. 6). The fixing control unit 65 drives the fixing motor M1 in response to the print signal for starting a print operation, and rotates the pressure roller 63, thereby conveying the sheet S conveyed to the fixing device 20 at a predetermined conveying speed.

The fixing control unit 65 also controls the temperature of the heater 60 by turning on the power supply control circuit 80 and passing electricity from the power supply control circuit 80 to the heat generating resistor 60b via the power supply electrode pattern of the heater 60 as a predetermined temperature control sequence according to the print signal. The fixing control unit 65 receives an output signal including information on the temperature in the paper passage area of the heater 60 output from the temperature detection member 64, and controls the power supply control circuit 80 based on the received output signal so that the temperature of the heater 60 can be maintained at a predetermined fixing temperature (target temperature).

[Conveyance speed and fixing temperature corresponding to the entered sheet type]
8 is a diagram showing the conveying speed in the fixing device 20 and the fixing temperature of the heater 60 set for each type of sheet S input from the print input unit 70. As shown in Fig. 8, the print input unit 70 of the first embodiment is configured to be able to input thin paper, regular paper, thick paper P1, thick paper P2, and thick paper P3 as types of sheet S. Each type has a different weight per unit area, and the heavier the weight per unit area, the thicker the sheet.

Thin paper is a type set for sheets with a weight per unit area of 60 to 74 g/ ^m2 . Plain paper is a type set for sheets with a weight per unit area of 75 to 90 g/ ^m2 . Thick paper P1 is a type set for sheets with a weight per unit area of 91 to 120 g/ ^m2 . Thick paper P2 is a type set for sheets with a weight per unit area of 121 to 160 g/ ^m2 . Thick paper P3 is a type set for sheets with a weight per unit area of 161 to 300 g/ ^m2 .

As shown in FIG. 8, the transport speed is set to 200 mm/s for thin paper and plain paper. The transport speed is set to 150 mm/s for thick paper P1, 100 mm/s for thick paper P2, and 65 mm/s for thick paper P3.

In the image forming device 1, when the conveying speed is the same, the higher the fixing temperature of the sheet S, the greater the amount of heat given to the sheet S. Also, in the image forming device 1, when the fixing temperature is the same, the slower the conveying speed of the sheet S, the greater the amount of heat given to the sheet S.

In the image forming device 1, when the surface roughness of the sheet S is the same, the heavier the weight per unit area of the sheet S, the greater the amount of heat required to fix the toner image carried on the sheet S to the sheet S. For this reason, in the image forming device 1 of the first embodiment, as shown in FIG. 8, the type of sheet S is set according to the weight per unit area, and the conveying speed and fixing temperature are set for each type of sheet S.

As shown in FIG. 8, in the image forming device 1, the same conveying speed is set for thin paper, which is the type with the lightest weight per unit area, and for plain paper, which is the second lightest weight per unit area, and this speed is set to be faster than the conveying speeds set for the other types. This is because, although the weights per unit area of thin paper and plain paper are different, even at the same conveying speed, the amount of heat required to fix the toner image can be sufficiently supplied by controlling the heating temperature of the fixing device 20. This speed faster than the conveying speeds set for the other types, which is set for thin paper and plain paper, constitutes the maximum image formation speed in the first embodiment.

In addition, in the image forming device 1, the fixing temperature for thick paper P1, which is the type of paper with the second lightest weight per unit area after plain paper, is set to the same as that for thin paper. This is because, although the weights per unit area of thin paper and thick paper P1 are different, even if the heating temperature is the same, the amount of heat required to fix the toner image can be sufficiently supplied by controlling the conveying speed of the fixing device 20.

With this configuration, when the conveying speed of the sheet S is slower than the conveying speed set for each type, the temperature is controlled to be lower than the fixing temperature set for each type, thereby preventing the amount of heat applied to the sheet S from becoming excessive.

[Fixing temperature corresponding to sheet type detected by type detection device]
As described above, in the type detection device 7, the weight per unit area is detected by the weight detection unit 30, and the surface roughness of the sheet S is detected by the surface property detection unit 40. In the image forming apparatus 1 of the first embodiment, the type of the sheet S on which an image is to be formed is determined from the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S. In the following description, the type of the sheet S detected by the type detection device 7 will also be referred to as the detected type, and the type of the sheet S input from the print input unit 70 will also be referred to as the input type.

When controlling the image forming unit 100 based on the detection type, the CPU 22 is configured to control the fixing temperature based on the weight per unit area of the sheet S and the surface roughness of the sheet S.

Figure 9 is a diagram showing the fixing temperature of the fixing device 20 according to the weight per unit area of the sheet S for each type of sheet S and the surface roughness of the sheet S. As described above, in the image forming device 1, when the surface roughness of the sheet S is the same, the heavier the weight per unit area of the sheet S, the greater the amount of heat required to fix the toner image carried on the sheet S to the sheet S. Also, in the image forming device 1, when the weight per unit area of the sheet S is the same, the rougher the surface roughness of the sheet S, the greater the amount of heat required to fix the toner image carried on the sheet S to the sheet S.

The CPU 22 of the first embodiment therefore sets the fixing temperature using the weight per unit area of the sheet S and the surface roughness of the sheet S when controlling the image forming unit 100 in accordance with the detection type to form an image on the sheet S. The CPU 22 sets one temperature as the fixing temperature by referring to the weight per unit area and the surface roughness of the sheet S from among the multiple types of temperatures prepared for each type of sheet S shown in FIG. 9.

In addition, the CPU 22 transports the sheet S at a transport speed corresponding to the type of the sheet S, whether the CPU 22 controls the image forming unit 100 according to the detection type or the input type.

Because of this configuration, the image forming device 1 of the first embodiment can form a good image by controlling the image forming unit 100 according to the detection type, making maximum use of the data on weight per unit area and surface roughness detected by the type detection device 7.

[Method of controlling image forming unit]
Next, a detailed description will be given of a case where the CPU 22 of the first embodiment controls the image forming unit 100 in accordance with a detection type and a case where the CPU 22 controls the image forming unit 100 in accordance with an input type.

As described above, when the CPU 22 controls the image forming unit 100 in accordance with the detection type, the CPU 22 sets the conveying speed and fixing temperature shown in FIG. 9 as the control contents for forming an image in accordance with the weight per unit area and surface roughness, which are the properties of the sheet S detected by the type detection device 7.

Therefore, when the image forming device 1 controls the image forming unit 100 according to the detection type, it can form a good image by making maximum use of the data on the weight per unit area and surface roughness detected by the type detection device 7. Of the controls of the image forming unit 100 that the CPU 22 can execute, the control of the image forming unit 100 according to the detection type constitutes the first mode in the first embodiment.

When the CPU 22 controls the image forming unit 100 in response to the input type input from the print input unit 70, the CPU 22 sets the conveying speed and fixing temperature shown in FIG. 8 as the control contents for forming an image.

Therefore, by controlling the image forming unit 100 according to the input type, the image forming device 1 may experience a decrease in image quality compared to when control is performed according to the detection type, but the conveying speed according to the input type is maintained, thereby satisfying the productivity required by the user. Of the controls of the image forming unit 100 that the CPU 22 can execute, the control of the image forming unit 100 according to the input type constitutes the second mode in the first embodiment.

Figure 10 is a flowchart showing the control process that the CPU 22 of the first embodiment executes to determine whether the image forming unit 100 is controlled in accordance with the detection type (first mode) or in accordance with the input type (second mode).

First, the CPU 22 determines whether the conveying speed of the sheet S corresponding to the input type is the maximum image forming speed (S101). In this process, the CPU 22 determines whether the productivity required by the user is the maximum productivity of the image forming device 1 by determining whether the conveying speed corresponding to the user's input is the maximum image forming speed.

If it is determined in the process of step S101 that the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed (No), the CPU 22 determines that the image forming unit 100 should be controlled at a conveying speed according to the input type (S102). In this process, the CPU 22 determines that the type of sheet S input by the user is one of thick paper P1 to P3, and therefore determines that an image should be formed at a conveying speed corresponding to the input type.

When the process of step S102 is executed, the CPU 22 detects the weight per unit area and surface roughness of the sheet S by the type detection device 7. If the input type and the detected type match, the CPU 22 decides to control in the first mode, and sets the fixing temperature of the heater 60 based on the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S.

In this way, the image forming device 1 of the first embodiment controls the image forming unit 100 in the first mode when the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed and the input type and the detection type match. This allows the image forming device 1 to form a good image by making maximum use of the data on the weight per unit area and surface roughness detected by the type detection device 7 when the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed.

On the other hand, when the input type and the detection type are different, the CPU 22 decides to control the image forming unit 100 in the second mode and sets the fixing temperature corresponding to the input type shown in FIG. 8. For example, when the weight per unit area of the sheet S corresponding to the input type is heavier than the detected weight per unit area, the CPU 22 sets the fixing temperature corresponding to the input type in order to prevent the sheet S from curling due to excessive heating. Also, when the weight per unit area of the sheet S corresponding to the input type is lighter than the detected weight per unit area, the CPU 22 sets the fixing temperature corresponding to the input type without changing the conveying speed in order to maintain the productivity required by the user.

In this way, the CPU 22 determines the control content of the image forming unit 100 when it is determined that the conveying speed of the sheet S corresponding to the input type is not the maximum image forming speed, and ends the control process that determines whether to control in the first mode or the second mode.

If it is determined in the processing of step S101 that the conveying speed of the sheet S corresponding to the input type is the maximum image formation speed (Yes), the CPU 22 detects the weight per unit area and the surface roughness of the sheet S using the type detection device 7 (S103).

Next, the CPU 22 determines whether the conveying speed corresponding to the detection type is the same as the maximum image formation speed (S104). In this process, the CPU 22 determines whether the detection type is thin paper or plain paper, which is associated with the maximum image formation speed as the conveying speed.

If it is determined in the process of step S104 that the conveying speed corresponding to the detection type is the same as the maximum image formation speed (Yes), the CPU 22 controls the image forming unit 100 according to the detection type to form an image on the sheet S (S105). In this process, the CPU 22 decides to control the image forming unit 100 in the first mode, and sets the fixing temperature of the heater 60 based on the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S.

On the other hand, if it is determined in the process of step S104 that the conveying speed corresponding to the detection type is different from the maximum image formation speed (No), the CPU 22 controls the image forming unit 100 according to the input type to form an image on the sheet S (S106). In this process, the CPU 22 decides to control the image forming unit 100 in the second mode, continues the conveying speed corresponding to the input type, and sets the fixing temperature corresponding to the input type shown in FIG. 8.

In this way, the CPU 22 determines the control content of the image forming unit 100 when it is determined that the conveying speed of the sheet S corresponding to the input type is the maximum image forming speed, and ends the control process that determines whether to control in the first mode or the second mode.

By executing such control processing, in the image forming device 1, when the CPU 22 sets the transport speed to the maximum image formation speed of 200 mm/s (first speed), the thickness of the sheet S corresponding to the input type is thin paper or plain paper (first thickness). Also, in the image forming device 1, when the CPU 22 sets the transport speed to a second speed (transport speed corresponding to thick papers P1 to P3) that is slower than the maximum image formation speed, the thickness of the sheet S corresponding to the input type is thick papers P1 to P3 (second thickness) that are thicker than the first thickness.

Therefore, the image forming device 1 of the first embodiment can appropriately heat the toner image on the sheet S according to the thickness of the sheet S by changing the conveying speed depending on the thickness corresponding to the type of sheet S input by the user, thereby forming a good image.

As described above, the image forming apparatus 1 of the first embodiment controls the image forming unit 100 in the first mode, making maximum use of the data on weight per unit area and surface roughness detected by the type detection device 7 to form a good image corresponding to the type of sheet S detected. Furthermore, the image forming apparatus 1 controls the image forming unit 100 in the second mode when the conveying speed corresponding to the input type is the maximum image formation speed and the conveying speed corresponding to the detection type is slower than the maximum image formation speed. In this way, the image forming apparatus 1 can form images without falling below the productivity set by the user by maintaining the maximum image formation speed corresponding to the input type, and can fully meet the user's demands.

In addition, the image forming device 1 of the first embodiment sets the conveying speed of the sheet S corresponding to the input type to the conveying speed corresponding to the input type when the conveying speed of the sheet S corresponding to the input type is faster than the conveying speed of the sheet S corresponding to the detection type. As a result, the image forming device 1 can form images without falling below the productivity set by the user by maintaining the conveying speed corresponding to the input type, and can fully meet the user's requirements.

Second Embodiment
Next, an image forming apparatus 1 according to a second embodiment will be described. The image forming apparatus 1 according to the second embodiment is configured to control the image forming unit 100 in the first mode when the conveying speed corresponding to the detection type is faster than the conveying speed corresponding to the input type. In this respect, the image forming apparatus 1 according to the second embodiment differs from the first embodiment described above. Since the other configurations are the same as those of the first embodiment, the same reference numerals are used to designate the components common to the first embodiment, and the description thereof will be omitted.

[Method of controlling image forming unit]
FIG. 11 is a flowchart showing a control process executed by the CPU 22 in the second embodiment to determine whether the image forming unit 100 is controlled in accordance with the detection type (first mode) or in accordance with the input type (second mode).

First, the CPU 22 detects the weight per unit area and the surface roughness of the sheet S using the type detection device 7 (S201). Next, the CPU 22 determines whether the conveying speed corresponding to the detection type is faster than the conveying speed corresponding to the input type (S202). In this process, the CPU 22 compares the conveying speed corresponding to the detection type with the conveying speed corresponding to the input type.

If it is determined in the process of step S202 that the conveying speed corresponding to the detection type is faster than the speed corresponding to the input type (Yes), the CPU 22 controls the image forming unit 100 according to the detection type to form an image on the sheet S (S203). In this process, the CPU 22 decides to control the image forming unit 100 in the first mode and sets the conveying speed to the one corresponding to the detection type. The CPU 22 also sets the fixing temperature of the heater 60 based on the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S.

On the other hand, if it is determined in the process of step S202 that the conveying speed corresponding to the detection type is the same as or slower than the conveying speed corresponding to the input type (No), the CPU 22 controls the image forming unit 100 according to the input type to form an image on the sheet S (S204). In this process, the CPU 22 decides to control the image forming unit 100 in the second mode, sets the conveying speed corresponding to the input type, and sets the fixing temperature corresponding to the input type shown in FIG. 8.

In this way, the CPU 22 compares the conveying speed of the sheet S corresponding to the detection type with the conveying speed of the sheet S corresponding to the input type to determine the control content of the image forming unit 100, and ends the control process that determines whether to control in the first mode or the second mode.

As described above, the image forming apparatus 1 of the second embodiment can form a good image according to the type of sheet S detected by making maximum use of the data on the weight per unit area and surface roughness detected by the type detection device 7 by controlling the image forming unit 100 in the first mode. Furthermore, when the conveying speed corresponding to the detection type is faster than the conveying speed corresponding to the input type, the image forming apparatus 1 can fully meet the user's demands by controlling the image forming unit 100 in the first mode to achieve productivity that exceeds the user's demands.

Third Embodiment
Next, an image forming apparatus 1 according to a third embodiment will be described. The image forming apparatus 1 according to the third embodiment is configured to change the fixing temperature from the temperature corresponding to the input type when the conveying speed corresponding to the input type is the maximum image forming speed and the conveying speed corresponding to the detection type is slower than the maximum image forming speed. In this respect, the image forming apparatus 1 according to the third embodiment is different from the first embodiment described above. Since the other configurations are the same as those of the first embodiment, the same reference numerals are used to designate the components common to the first embodiment, and the description thereof will be omitted.

[Method of controlling image forming unit]
FIG. 12 is a flowchart showing a control process executed by the CPU 22 in the third embodiment to determine whether the image forming unit 100 is controlled in accordance with the detection type (first mode) or in accordance with the input type (second mode).

First, the CPU 22 determines whether the conveying speed of the sheet S corresponding to the input type is the maximum image forming speed (S301). In this process, the CPU 22 determines whether the productivity required by the user is the maximum productivity of the image forming device 1 by determining whether the conveying speed corresponding to the user's input is the maximum image forming speed.

If it is determined in the process of step S301 that the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed (No), the CPU 22 determines to control the image forming unit 100 at a conveying speed according to the input type (S302). In this process, the CPU 22 determines to form an image at a conveying speed corresponding to the input type because the type of sheet S input by the user is one of thick paper P1 to P3.

When the process of step S302 is executed, the CPU 22 detects the weight per unit area and surface roughness of the sheet S by the type detection device 7. If the input type and the detected type match, the CPU 22 decides to control in the first mode, and sets the fixing temperature of the heater 60 based on the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S.

In this way, the image forming device 1 of the third embodiment controls the image forming unit 100 in the first mode when the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed and the input type and the detection type match. This allows the image forming device 1 to form a good image by making maximum use of the data on the weight per unit area and surface roughness detected by the type detection device 7 when the conveying speed of the sheet S corresponding to the input type is not the maximum image formation speed.

On the other hand, when the input type and the detection type are different, the CPU 22 decides to control the image forming unit 100 in the second mode. When the weight per unit area of the sheet S corresponding to the input type is heavier than the weight per unit area detected, the CPU 22 in the third embodiment sets the fixing temperature corresponding to the input type shown in FIG. 8 in order to prevent curling of the sheet S due to excessive heating.

On the other hand, when the weight per unit area of the sheet S corresponding to the input type is lighter than the detected weight per unit area, the CPU 22 does not change the conveying speed in order to maintain the productivity required by the user. Also, since the CPU 22 forms an image on a type of sheet S that is heavier per unit area than the sheet corresponding to the input type and requires more heat to form an image, the CPU 22 sets the maximum fixing temperature for the type of sheet corresponding to the input type among the fixing temperatures shown in FIG. 9. For example, when the input type is thick paper P1 and the detected type is thick paper P3, the CPU 22 sets the fixing temperature to 190° C., which is the maximum fixing temperature for thick paper P1.

By maintaining a conveying speed corresponding to the input type, the image forming device 1 can form images without falling below the productivity set by the user, and can fully meet the user's requirements. Furthermore, when a sheet is heavier per unit area than a sheet corresponding to the input type, the image forming device 1 heats the sheet at the highest temperature from among multiple fixing temperatures according to the sheet type, and can form good images while fully meeting the user's requirements.

In this way, the CPU 22 determines the control content of the image forming unit 100 when it is determined that the conveying speed of the sheet S corresponding to the input type is not the maximum image forming speed, and ends the control process that determines whether to control in the first mode or the second mode.

If it is determined in the processing of step S301 that the conveying speed of the sheet S corresponding to the input type is the maximum image formation speed (Yes), the CPU 22 detects the weight per unit area and the surface roughness of the sheet S using the type detection device 7 (S303).

Next, the CPU 22 determines whether the conveying speed corresponding to the detection type is the same as the maximum image formation speed (S304). In this process, the CPU 22 determines whether the detection type is thin paper or plain paper, which is associated with the maximum image formation speed as the conveying speed.

If it is determined in the process of step S304 that the conveying speed corresponding to the detection type is the same as the maximum image formation speed (Yes), the CPU 22 controls the image forming unit 100 according to the detection type to form an image on the sheet S (S305). In this process, the CPU 22 decides to control the image forming unit 100 in the first mode, and sets the fixing temperature of the heater 60 based on the weight per unit area of the sheet S detected by the type detection device 7 and the surface roughness of the sheet S.

On the other hand, in the process of step S304 , if it is determined that the conveying speed corresponding to the detection type is different from the maximum image forming speed (No), the CPU 22 controls the image forming unit 100 according to the input type to form an image on the sheet S (S306). In this process, the CPU 22 determines to control the image forming unit 100 in the second mode and continues the conveying speed corresponding to the input type. In addition, the CPU 22 sets the maximum fixing temperature for the sheet type corresponding to the input type among the fixing temperatures shown in FIG. 9. For example, when the input type is plain paper and the detection type is thick paper P1, the CPU 22 sets the fixing temperature to 200° C., which is the maximum fixing temperature for plain paper.

In this way, the CPU 22 determines the control content of the image forming unit 100 when it determines that the conveying speed of the sheet S corresponding to the input type is the maximum image forming speed, and ends the control process that determines whether to control in the first mode or the second mode.

As described above, the image forming apparatus 1 of the third embodiment can form a good image according to the type of the detected sheet S by making maximum use of the data of the weight per unit area and surface roughness detected by the type detection device 7 by controlling the image forming unit 100 in the first mode. In addition, when the conveying speed corresponding to the input type is the maximum image formation speed and the conveying speed corresponding to the detection type is slower than the maximum image formation speed, the image forming apparatus 1 controls the image forming unit 100 in the second mode. In this way, the image forming apparatus 1 can form an image without falling below the productivity set by the user by maintaining the maximum image formation speed, and can fully meet the user's requirements. In addition, when the sheet has a weight per unit area heavier than the sheet corresponding to the input type, the image forming apparatus 1 can form a good image while fully meeting the user's requirements by heating it at the highest temperature from among multiple fixing temperatures according to the sheet type.

<Other embodiments>
In the first to third embodiments, the image forming apparatus 1 is configured to be able to input information related to the type of the sheet S as the print settings that can be input from the print input unit 70, but is not limited to this. The image forming apparatus 1 may be configured to be able to input the weight per unit area of the sheet S and the surface roughness of the sheet S as the print settings that can be input from the print input unit 70.

When configured in this manner, when the CPU 22 controls the image forming unit 100 in the second mode, it can set the fixing temperature according to the weight per unit area and surface roughness of the sheet S input from the print input unit 70. Therefore, even when the image forming device 1 controls the image forming unit 100 in the second mode, it can set the fixing temperature according to the weight per unit area and surface roughness input, making it possible to form good images while fully meeting the user's needs.

In addition, in the first to third embodiments, when controlling the image forming unit 100 in the first mode, the CPU 22 sets the fixing temperature using the weight per unit area of the sheet S and the surface roughness of the sheet S, but this is not limited to this. When controlling the image forming unit 100 in the first mode, the CPU 22 may be configured to set the fixing temperature using the weight per unit area of the sheet S, regardless of the surface roughness of the sheet S. Also, when controlling the image forming unit 100 in the first mode, the CPU 22 may be configured to set the fixing temperature using the surface roughness of the sheet S, regardless of the weight per unit area of the sheet S.

In the first to third embodiments, the image forming device 1 is configured to receive sheet type information from the user via the print input unit 70 provided in the device, but is not limited to this. The image forming device 1 may be configured to receive sheet type information from the user via an external terminal such as an external computer.

In addition, in the first to third embodiments, when controlling the image forming unit 100 in the first mode, the CPU 22 is configured to set the fixing temperature according to the weight per unit area and surface roughness of the sheet S, but is not limited to this. When controlling the image forming unit 100 in the first mode, the CPU 22 may control various operations related to image formation performed by the image forming unit 100 using information detected by the type detection device 7, such as the toner concentration and the conveying speed in the transfer unit 10, in addition to the fixing temperature.

In the first to third embodiments, the image forming apparatus 1 has the type detection device 7 disposed between the registration rollers 6 and the transfer unit 10 on the transport path of the sheet S, but this is not limited thereto. The image forming apparatus 1 only needs to have the type detection device 7 disposed at a position on the transport path upstream of the fixing device 20 in the transport direction of the sheet S.

In the first to third embodiments, the image forming device 1 includes a weight detection unit 30 that detects the weight per unit area using ultrasonic waves, but is not limited to this. The image forming device 1 may be configured to detect the weight per unit area of the sheet S, for example, from the power consumption of the fixing device 20 while the sheet is passing through. The image forming device 1 may be configured to detect the weight per unit area of the sheet S, for example, from the temperature difference between the fixing film 61 and the heater 60.

In the first to third embodiments, the CPU 22 is configured to control the conveying speed in the fixing device 20 as the process speed according to the type of sheet S, but is not limited to this. The CPU 22 may also be configured to control the conveying speed when conveyed by the paper feed rollers 5 and the registration rollers 6, and the conveying speed when conveyed by the drive rollers 18, based on information detected by the type detection device 7.

1... Image forming device: 7... Detection means (type detection device): 10... Transfer section: 20... Fixing section (fixing device): 22... CPU (control section): 70... Reception means (print input section): 100... Image forming section: S... Sheet

Claims (11)

an image forming unit that conveys a sheet according to a process speed while forming an image on the sheet;
a detection unit for detecting a type of a sheet to be conveyed to the image forming unit;
A receiving means for receiving information on the type of sheet from a user;
a control unit capable of executing a first mode in which the image forming unit is controlled in accordance with the type of sheet detected by the detection unit, and a second mode in which the image forming unit is controlled in accordance with the type of sheet received by the reception unit,
the control unit controls the image forming unit in the second mode when the process speed corresponding to the type of sheet accepted by the accepting unit is faster than the process speed corresponding to the type of sheet detected by the detecting unit.
1. An image forming apparatus comprising: The control unit is
When controlling the image forming unit in the first mode, a control content for forming an image is set according to the property of the sheet detected by the detection unit;
when controlling the image forming unit in the second mode, a control content corresponding to the type of the sheet received by the receiving unit is set.
2. The image forming apparatus according to claim 1, The image forming unit includes:
A transfer unit that transfers an image onto a sheet;
A fixing section that heats the image transferred to the sheet at a fixing temperature to fix the image.
3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction. The detection means detects the surface roughness of the sheet,
the control unit sets the fixing temperature based on the surface roughness of the sheet detected by the detection unit when controlling the image forming unit in the first mode.
4. The image forming apparatus according to claim 3. The detection means detects the weight per unit area of the sheet,
the control unit sets the fixing temperature based on the weight per unit area of the sheet detected by the detection unit when controlling the image forming unit in the first mode.
5. The image forming apparatus according to claim 3, wherein the image forming apparatus is a multi-color image forming apparatus. the control unit sets the fixing temperature corresponding to the type of the sheet received by the receiving unit when controlling the image forming unit in the second mode.
6. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium. The control unit is
The fixing temperature can be set to any one of a plurality of temperatures according to the type of sheet,
when controlling the image forming unit in the second mode, the highest temperature among the plurality of temperatures corresponding to the type of sheet received by the receiving unit is set as the fixing temperature.
6. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium. The control unit is
When controlling the image forming unit in the first mode, the process speed is set in accordance with a type of sheet;
when the process speed corresponding to the type of sheet received by the receiving unit is slower than a first speed which is a maximum speed among the settable process speeds , controlling the image forming unit in the first mode;
8. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction. The type of sheet includes information related to the thickness of the sheet,
When the control unit sets the process speed to the first speed, a thickness of a sheet corresponding to the type of the sheet received by the receiving unit is a first thickness,
When the control unit sets the process speed to a second speed slower than the first speed, a thickness of the sheet corresponding to the type of the sheet received by the receiving unit is a second thickness thicker than the first thickness.
9. The image forming apparatus according to claim 8, the control unit controls the image forming unit in the first mode when the process speed corresponding to the type of sheet detected by the detection unit is faster than the process speed corresponding to the type of sheet accepted by the acceptance unit.
8. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction. an image forming unit that conveys a sheet according to a process speed while forming an image on the sheet;
a detection unit for detecting a type of a sheet to be conveyed to the image forming unit;
A receiving means for receiving information on the type of sheet from a user;
a control unit capable of setting the process speed,
the control unit, when the process speed corresponding to the type of sheet accepted by the accepting unit is faster than the process speed corresponding to the type of sheet detected by the detection unit, sets the process speed to the process speed corresponding to the type of sheet accepted by the accepting unit.
1. An image forming apparatus comprising:

Images