JP5667965B2 - Image forming apparatus - Google Patents

Description

 The present invention relates to an image forming apparatus.

2. Description of the Related Art Conventionally, in image forming apparatuses such as printers, copiers, and multifunction machines, a technique for automatically detecting the size of paper set in a paper feed cassette using various paper size detection mechanisms is known. (See Patent Documents 1 to 3 below).
A general paper size detection mechanism is often configured by a combination of a restricting plate and a switch used for restricting the position of the paper. When this switch type paper size detection mechanism is used, the paper size can be determined by checking which switch is turned on when the paper position is restricted by moving the restriction plate.

JP 2009-190889 A Japanese Patent Laid-Open No. 3-166129 JP-A-8-34525

  The switch type paper size detection mechanism automatically determines the paper size when the paper whose size can be determined is limited to standard paper, and the paper whose size cannot be determined (non-standard paper) is set in the paper cassette. This cannot be done, and it has been necessary to manually set the magnification of the image to be printed on the paper. In addition, in order to automatically determine the size of the irregular sheet, it is necessary to greatly increase the number of switches, resulting in a significant increase in component costs.

 The present invention has been made in view of the above-described circumstances, and can automatically determine the paper size regardless of the standard size paper or the irregular size paper, and increases the component cost for realizing the automatic paper size determination. An object of the present invention is to provide an image forming apparatus capable of suppressing the above.

 In order to solve the above problems, in the present invention, as a first solving means related to an image forming apparatus, a paper sensor that outputs a signal according to the presence or absence of paper, and four sides of paper set in a paper feed cassette are provided. A paper sensor moving means for moving the paper sensor so as to draw a linear trajectory intersecting two sides sharing one vertex, a position sensor for outputting a signal corresponding to the position of the paper sensor, and the paper And a paper size determining means for determining the size of the paper based on an output signal of the sensor and the position sensor.

  In the present invention, as a second solving means relating to the image forming apparatus, in the first solving means, the paper sensor moving means moves the paper sensor in conjunction with a slide operation of the paper feeding cassette. A means of moving in a direction perpendicular to the slide direction of the paper feed cassette is employed.

  In the present invention, as a third solving means relating to the image forming apparatus, in the first or second solving means, the paper size determining means indicates that the output signal of the paper sensor indicates that there is no paper from no paper. The size of the paper is determined based on the output signal of the position sensor when the state is changed and the output signal of the position sensor when the output signal of the paper sensor is changed from being present to being in a state indicating no paper. Adopt the means to do.

 According to the present invention, it is possible to automatically determine the paper size regardless of the standard paper and the non-standard paper, and it is possible to suppress an increase in the component cost in realizing the automatic paper size determination.

1 is a block diagram illustrating a schematic configuration of a multifunction peripheral A according to the present embodiment. FIG. 2 is a front view and a left side view of the multifunction machine A. The state in which the paper sensor 7 moves in conjunction with the slide operation of the paper feed cassette 10 is illustrated. The movement trajectory R of the sheet sensor 7 viewed from the sheet cassette 10 is shown. 6 is a flowchart illustrating a paper size determination process executed by a control unit 6. It is an example of a paper size determination table used for paper size determination processing.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Hereinafter, as an image forming apparatus according to the present invention, a multi-function machine having functions such as a copier, a printer, a scanner, and a facsimile will be described as an example.
FIG. 1 is a block diagram illustrating a schematic configuration of a multifunction peripheral A according to the present embodiment. As shown in FIG. 1, the multifunction peripheral A includes an operation display unit 1, an image reading unit 2, an image data storage unit 3, a communication unit 4, an image forming unit 5, a control unit 6, a sheet sensor 7, and a sheet sensor movement. A mechanism 8 and a position sensor 9 are provided.

 The operation display unit 1 includes an operation key 1a and a touch panel 1b, and functions as a man-machine interface that associates the user with the multifunction peripheral A. The operation display unit 1 outputs an operation signal of an operation button pressed by a user or an operation button displayed on the touch panel 1b to the control unit 6, and various operations are performed on the touch panel 1b based on the control signal of the control unit 6. Display an image.

 The image reading unit 2 is based on a control signal input from the control unit 6 and is automatically conveyed by an ADF (Automatic Document Feeder) or a surface image (original document) placed on a platen glass. The image) is read by the line sensor and converted into document image data, and the document image data is output to the image data storage unit 3.

 The image data storage unit 3 is a semiconductor memory, a hard disk device, or the like, and is based on a control signal input from the control unit 6 and original image data or a print image that the communication unit 4 receives from an external client computer (not shown). Data and facsimile image data received by the communication unit 4 from the facsimile apparatus are stored, and these image data are read out based on a control signal input from the control unit 6 and output to the image forming unit 5.

 The communication unit 4 communicates with an external multifunction peripheral or facsimile apparatus via a telephone line based on a control signal input from the control unit 6, or with a client computer via a LAN (Local Area Network). . That is, the communication unit 4 has both a communication function compliant with a LAN standard such as Ethernet (registered trademark) and a communication function compliant with a facsimile standard such as G3.

 The image forming unit 5 includes a print engine (photosensitive drum, charger, developing device, fixing roller, and the like) and the like, and 1 sets the paper set in the paper feed cassette based on a control signal input from the control unit 6. Each sheet is fed and conveyed, a toner image is formed on the sheet based on the image data input from the image data storage unit 3, and the sheet is discharged to the outside after the toner image is fixed.

 The control unit 6 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an interface circuit that transmits and receives various signals to and from the above-described units, and is stored in the ROM. The overall operation of the multifunction device A is controlled based on the control program.

 In addition to the above-described components, the multifunction peripheral A includes a paper sensor 7, a paper sensor moving mechanism 8, and a position sensor 9 as characteristic components for detecting the size of the paper set in the paper feed cassette. ing. Hereinafter, the paper sensor 7, the paper sensor moving mechanism 8, and the position sensor 9 will be described with reference to FIGS.

 2A is a diagram of the multifunction device A viewed from the front, and FIG. 2B is a diagram of the multifunction device A viewed from the left side. In FIG. 2, reference numeral 10 denotes a paper feeding cassette, and reference numeral P denotes a paper set in the paper feeding cassette 10. In the following, the positional relationship of each member will be described with reference to an XYZ orthogonal coordinate system in which the height direction of the multifunction peripheral A is the Z axis, the width direction is the X axis, and the depth direction is the Y axis.

 As shown in FIG. 2, the paper feed cassette 10 is slidably (inserted / removed) between the inner side and the outer side of the multifunction peripheral A along the Y-axis direction. A rack gear 8a extends in the Y-axis direction at the left end of the lower surface of the paper feed cassette 10 with the teeth facing downward. A pinion gear 8b that meshes with the rack gear 8a is rotatably installed below the paper feed cassette 10 in the multifunction machine A.

 A ball screw 8c extending in the X-axis direction is connected to the rotation center of the pinion gear 8b. A slider 8d that is movable in the axial direction of the ball screw 8c, that is, in the X-axis direction by the rotation of the ball screw 8c is attached to the ball screw 8c. These rack gear 8a, pinion gear 8b, ball screw 8c, and slider 8d constitute a paper sensor moving mechanism 8.

On the upper surface of the slider 8d, a paper sensor 7 for outputting a signal corresponding to the presence or absence of the paper P to the control unit 6 is attached. That is, the paper sensor 7 is movable in the X-axis direction together with the slider 8d below the paper feed cassette 10. The paper sensor 7 is an optical reflection sensor or an ultrasonic sensor, for example, and detects the presence or absence of the paper P by transmitting a reference signal (an optical signal or an ultrasonic wave) upward in the Z-axis direction. While a high level signal is output, a low level signal is output when paper is present.
When an optical reflection sensor is used as the paper sensor 7, the lower surface of the paper feed cassette 10 (at least the surface corresponding to the movement path of the paper sensor 7) is formed of a light transmissive member such as a transparent plate. (Or a notch may be provided in the lower surface of the paper feed cassette 10).

 A position sensor 9 that outputs a signal corresponding to the position of the paper sensor 7 to the control unit 6 is attached to one end of the ball screw 8c (the end opposite to the pinion gear 8b). The position sensor 9 only needs to change its output signal by the rotation of the ball screw 8c. For example, a variable resistor or a rotary encoder can be used.

 By using the paper sensor moving mechanism 8 constituted by the rack gear 8a, the pinion gear 8b, the ball screw 8c, and the slider 8d as described above, the paper sensor 7 is linked to the slide operation (insertion / removal operation) of the paper feed cassette 10. It can be moved in a direction perpendicular to the slide direction of the paper feed cassette 10 (that is, in the X-axis direction).

 FIG. 3 illustrates a state in which the paper sensor 7 moves in conjunction with the slide operation of the paper feed cassette 10. As shown in FIG. 3, the paper sensor 7 moves in the X-axis direction together with the slider 8d in conjunction with the insertion operation of the paper feed cassette 10 (the operation of sliding the paper feed cassette 10 from the outside to the inside of the multifunction device A). It moves by a certain length L from the right side to the left side.

 On the contrary, the paper sensor 7 is linked with the slider 8d from the left side to the right side of the X axis in conjunction with the pulling out operation of the paper feeding cassette 10 (the operation of sliding the paper feeding cassette 10 from the inside to the outside of the multi-function device A). Move by the same length L (not shown). In this way, the paper sensor 7 reciprocates left and right within a certain length L on the X axis in conjunction with the slide operation of the paper feed cassette 10.

 FIG. 4 shows the movement locus of the paper sensor 7 as viewed from the paper feed cassette 10. As shown in FIG. 4, when viewed from the paper feed cassette 10, the paper sensor 7 is linked to the sliding operation of the paper feed cassette 10, and one of the four sides of the paper P set in the paper feed cassette 10. It moves so as to draw a linear trajectory R that intersects two sides sharing one vertex.

  4A shows a case where a maximum size paper P (for example, Ledger paper) is set in the paper feed cassette 10, and FIG. 4B shows a case where a minimum size paper P (eg, Statement paper) is set in the paper feed cassette 10. The case is illustrated. As shown in these drawings, the paper sensor 7 detects that the paper P is set from the paper feed cassette 10 regardless of the size of the paper P if the paper P is set at a predetermined position (for example, the center right justified position) in the paper feed cassette 10. When viewed, the line P always moves while drawing a linear trajectory R that intersects two sides sharing one vertex of the four sides of the sheet P.

Therefore, if the position sensor 9 can be used to know the position of the paper sensor 7 on the X axis at each of two points (intersections R1 and R2) where the movement locus R of the paper sensor 7 and the paper P intersect, The size of the paper P can be determined from the geometric relationship between the movement locus R of the paper sensor 7 and the X axis (the inclination angle θ of the movement locus R with respect to the X axis).
The above is the description of the configuration of the multifunction device A. Hereinafter, the operation of the multifunction device A configured as described above, in particular, the control unit 6 based on the output signals of the paper sensor 7 and the position sensor 9 will be described. An operation for determining the size of the paper P set in the paper feed cassette 10 will be described.

 As shown in FIG. 3, when the paper feed cassette 10 is completely located outside the multi-function peripheral A, the paper sensor 7 is located at the origin position (the rightmost position) on the X axis, In conjunction with the insertion operation of the paper cassette 10 (the operation of sliding the paper supply cassette 10 from the outside to the inside of the multi-function device A), the paper sensor 7 has a certain length L from the origin position on the X axis toward the left side. Moving. As a result, when viewed from the sheet cassette 10, the sheet sensor 7 moves along a linear locus R that intersects two sides sharing one vertex of the four sides of the sheet P (see FIG. 4).

 When the control unit 6 detects that the insertion operation of the paper feed cassette 10 has been started based on the output signal of the position sensor 9 (that is, the paper sensor 7 has started to move), the control unit 6 follows the flowchart shown in FIG. Execute the judgment process.

 As shown in FIG. 5, when the paper size determination process is started, the control unit 6 first monitors the output signal of the paper sensor 7 (step S1), and the output signal of the paper sensor 7 indicates that there is no paper from no paper. It is determined whether or not the state has changed, that is, whether or not the state has changed from the high level to the low level (step S2).

 If “No” in step S 2, the control unit 6 proceeds to a process in step S 4, which will be described later. On the other hand, if “Yes” in step S 2, the paper sensor 7 The position X1 of the paper sensor 7 on the X-axis when the output signal changes from the high level to the low level is acquired (step S3).

 The position X1 of the sheet sensor 7 obtained here indicates the position of the sheet sensor 7 on the X axis at the first intersection R1 between the movement locus R of the sheet sensor 7 and the sheet P. When the position sensor 7 is of a type that outputs an analog voltage corresponding to the position of the paper sensor 7 such as a variable resistor, the output signal (analog voltage) of the position sensor 7 is A / D converted. The digital voltage value obtained in this way may be acquired as the position X1 of the paper sensor 7.

 The control unit 6 determines whether the output signal of the sheet sensor 7 has changed from the presence of the sheet to the state indicating the absence of the sheet in the case of “No” in step S2 or after the completion of the process in step S3. It is determined whether or not the level has changed (step S4).

 If “No” in step S4, the control unit 6 returns to the process of step S1. If “Yes” in step S4, the control unit 6 outputs the paper sensor 7 based on the output signal of the position sensor 7. The position X2 on the X axis of the paper sensor 7 when the signal changes from the low level to the high level is acquired (step S5).

 The position X2 of the sheet sensor 7 obtained here indicates the position of the sheet sensor 7 on the X axis at the second intersection R2 between the movement locus R of the sheet sensor 7 and the sheet P. When the position sensor 7 is of a type that outputs an analog voltage corresponding to the position of the paper sensor 7 such as a variable resistor, the output signal (analog voltage) of the position sensor 7 is A / D converted. The digital voltage value obtained in this way may be acquired as the position X2 of the paper sensor 7.

 Finally, the control unit 6 determines the size of the paper P set in the paper feed cassette 10 based on the positions X1 and X2 of the paper sensor 7 acquired in steps S3 and S5 (step S6). Specifically, the control unit 6 determines the vertical size (Y-axis direction size) of the paper P from the position X1 of the paper sensor 7 while referring to the paper size determination table stored in the internal memory in advance. The lateral size (size in the X-axis direction) of the paper P is determined from the position X2 of the paper sensor 7.

 FIG. 6 shows an example of the paper size determination table (for example, θ = 34 °). As described above, the paper size determination table is table data indicating the correspondence between the position on the X axis of the paper sensor 7 (for example, the output voltage value of the variable resistor), the paper vertical size, and the paper horizontal size. For example, the control unit 6 sets the output voltage value of the variable resistor corresponding to the position X1 of the paper sensor 7 (the position of the paper sensor 7 when the output of the paper sensor 7 is changed from the high level to the low level) to 0.5 V. In this case, it is determined that the vertical size of the paper P is 288.2 mm. Further, the control unit 6 determines that the output voltage value of the variable resistor corresponding to, for example, the position X2 of the paper sensor 7 (the position of the paper sensor 7 when the output of the paper sensor 7 changes from low level to high level) is 3. In the case of 41V, it is determined that the horizontal size of the paper P is 319.4 mm.

 As described above, according to the present embodiment, since the vertical and horizontal sizes of the paper P set in the paper feeding cassette P can be determined in mm units, the paper size can be determined regardless of the standard paper and the irregular paper. Automatic determination is possible, and the magnification setting of an image to be printed on paper can be automatically performed. In addition, according to the present embodiment, only the paper sensor 7, the paper sensor moving mechanism 8, and the position sensor 9 are necessary to realize the automatic determination of the paper size as described above, so that the component cost increases. Can be suppressed.

In addition, this invention is not limited to the said embodiment, The following modifications are mentioned.
(1) In the above embodiment, the paper sensor moving mechanism 8 moves the paper sensor 7 in a direction (X axis) orthogonal to the slide direction (Y axis direction) of the paper feed cassette 10 in conjunction with the slide operation of the paper feed cassette 10. The sheet sensor 7 is drawn so as to draw a linear trajectory R that intersects two sides sharing one vertex among the four sides of the sheet P set in the sheet feeding cassette 10 by adopting the configuration of moving in the direction). Was moving.
Instead of such a configuration, after the paper feed cassette 10 is completely stored in the multifunction peripheral A, the two sides sharing one vertex among the four sides of the paper P set in the paper feed cassette 10 and A configuration may be adopted in which the sheet sensor 7 is moved obliquely with respect to the Y-axis direction so as to draw intersecting linear trajectories R.
Further, if the structure is possible, a configuration in which the sheet sensor 7 is disposed above the sheet cassette 10 may be employed.

(2) In the above embodiment, the image forming apparatus according to the present invention has been described with reference to the multifunction peripheral A. However, the present invention is not limited to this, and other image formation such as a copier, a printer, a scanner, and a facsimile machine is performed. It can be applied to the device.

 A ... MFP, 1 ... operation display unit, 2 ... image reading unit, 3 ... image data storage unit, 4 ... communication unit, 5 ... image forming unit, 6 ... control unit, 7 ... paper sensor, 8 ... paper sensor movement Mechanism, 9 ... Position sensor, P ... Paper

Claims (2)

A paper sensor that outputs a signal according to the presence of paper,
Paper sensor moving means for moving the paper sensor so as to draw a linear trajectory intersecting two sides sharing one vertex among the four sides of the paper set in the paper feed cassette;
A position sensor that outputs a signal corresponding to the position of the paper sensor;
Paper size determination means for determining the size of the paper based on output signals of the paper sensor and the position sensor;
Bei to give a,
The image forming apparatus, wherein the sheet sensor moving means moves the sheet sensor in a direction orthogonal to a sliding direction of the sheet feeding cassette in conjunction with a sliding operation of the sheet feeding cassette . The paper size determination means is a state in which the output signal of the position sensor when the output signal of the paper sensor changes from the absence of paper to a state indicating the presence of paper, and the output signal of the paper sensor indicates the presence of paper from the presence of paper The image forming apparatus according to claim 1, wherein the size of the sheet is determined based on an output signal of the position sensor when the position changes .

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