JP2013112494A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing power consumption in the automatic determination of a size of a paper sheet.SOLUTION: The image forming apparatus includes: a paper sheet sensor which outputs a signal corresponding to the presence and absence of the paper sheet; a paper sheet sensor moving means of moving the paper sheet sensor drawing a linear track crossing two sides sharing one vertex among four sides of the paper sheet set in a paper feed cassette; a position sensor which outputs a signal corresponding to the position of the paper sheet sensor; and a control means of turning on or off the paper sheet sensor according to the position of the paper sheet sensor grasped from the output signal of the position sensor. The control means turns on the paper sheet sensor only at positions of the paper sheet sensor at two intersections of the paper sheet and track which are preset by the size of the paper sheet. On the basis of an output signal of the paper sheet sensor obtained at the on-state, the size of the paper sheet is determined.

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 and 2 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 2004-75306 A JP 2005-330068 A

  The conventional technology has a problem in that power consumption increases because the sensors are always in an on state during automatic paper size determination.

 SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing power consumption during automatic determination of a paper size.

 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 sheet sensor moving means for moving the sheet 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 sheet sensor, and the position Control means for switching the paper sensor to an operation-on state or an operation-off state according to the position of the paper sensor ascertained from the output signal of the sensor, and the control means is configured to preset the paper for each paper size. The paper sensor is turned on only at the position of the paper sensor at two intersections of the trajectory and the trajectory, and the paper sensor obtained at that time Adopting means of determining the size of the paper output signal based on the.

  In the present invention, as the second solving means relating to the image forming apparatus, in the first solving means, the control means outputs an output signal of the paper sensor obtained when the paper sensor is turned on. When there is a sheet, it is obtained when the sheet sensor is turned off after determining the size of the sheet from the position of the sheet sensor when the operation is turned on, while the sheet sensor is turned on. When the output signal of the paper sensor indicates that there is no paper, a means is adopted in which the paper sensor is immediately turned off.

  According to the present invention, as a third solving means related to the image forming apparatus, in the first or second solving means, the paper sensor moving means is linked to the slide operation of the paper feed cassette, and the paper is moved. A means is adopted in which the sensor is moved in a direction perpendicular to the slide direction of the paper feed cassette.

 According to the present invention, power consumption during automatic determination of paper size can be reduced.

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. FIG. 6 is a diagram illustrating the position of the sheet sensor 7 at two intersections R1 and R2 between a movement locus R of the sheet sensor 7 set in advance for each sheet size and a sheet P of each size. 6 is a flowchart illustrating a paper size determination process executed by a control unit 6.

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).
The paper sensor 7 is switched by the control unit 6 to an operation on state (power on state) or an operation off state (power off state).

 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 (origin position of the paper sensor 7) toward 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).

 On the contrary, as shown in FIG. 5, when the size of the paper P to be used is known (when the paper P is a standard paper), the movement path R of the paper sensor 7 and the paper P of each size for each paper size. The position of the sheet sensor 7 at the two intersections R1 and R2 can be obtained in advance by calculation. That is, referring to FIG. 5, for example, if a low level signal indicating the presence of paper is output from the paper sensor 7 when the position of the paper sensor 7 is X1_R1, the vertical size (size in the Y-axis direction) of the paper P is 279. 4 mm, and for example, if the paper sensor 7 is at X14_R2 and the paper sensor 7 outputs a high level signal indicating no paper, the horizontal size of the paper P (size in the X-axis direction) is 431. .8 mm can be determined.

As described above, the control unit 6 according to the present embodiment is configured so that the sheet sensor 7 is only at the position of the sheet sensor 7 at the two intersections R1 and R2 between the sheet P preset for each sheet size and the movement locus R of the sheet sensor 7. Is turned on, and the size of the paper P is determined based on the output signal of the paper sensor 7 obtained at that time, thereby reducing the power consumption during automatic determination of the paper size.
In the following, the operation of the MFP A configured as described above, in particular, the control unit 6 is set in the paper feed cassette 10 while suppressing power consumption based on the output signals of the paper sensor 7 and the position sensor 9. An operation for determining the size of the paper P 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. In the initial state, the control unit 6 controls the paper sensor 7 to be in an operation off state.

 As shown in FIG. 6, when the paper size determination process is started, the control unit 6 first grasps the position of the paper sensor 7 based on the output signal of the position sensor 9 (step S1), and the position of the paper sensor 7 is determined. Whether any of the positions of the sheet sensor 7 at the intersection R1 between the sheet P preset for each sheet size and the movement locus R of the sheet sensor 7 (any one of X1_R1 to X13_R1 in FIG. 5) is met. Determine (step S2).

 If “No” in step S2, the control unit 6 returns to the process of step S1. If “Yes” in step S2, the control unit 6 switches the paper sensor 7 to the operation-on state (step S3). It is determined whether or not the output signal of the sensor 7 is at a low level (step S4).

When “Yes” is determined in step S4 (that is, when there is a sheet), the control unit 6 determines the vertical size of the sheet P from the position of the sheet sensor 7 when the operation is turned on (step S5). Then, after the paper sensor 7 is switched to the operation-off state, the process proceeds to step S8 described later (step S6). In step S5, the control unit 6 determines that the vertical size of the paper P is 279.4 mm when the position of the paper sensor 7 is X1_R1 when the operation is turned on, for example (see FIG. 5).
On the other hand, if “No” is determined in step S4 (that is, when there is no paper), the control unit 6 immediately switches the paper sensor 7 to the operation-off state and then returns to the process of step S1 (step S7).

 After the end of step S6, the control unit 6 grasps the position of the sheet sensor 7 based on the output signal of the position sensor 9 (step S8), and the position of the sheet sensor 7 is set in advance for each sheet size. It is determined whether or not any of the positions of the paper sensor 7 (any of X14_R2 to X26_R2 in FIG. 5) at the intersection R2 between P and the movement locus R of the paper sensor 7 (step S9).

 If “No” in step S9, the control unit 6 returns to the process of step S8. On the other hand, if “Yes” in step S9, the control unit 6 switches the paper sensor 7 to the operation-on state (step S10). It is determined whether or not the output signal of the paper sensor 7 is at a high level (step S11).

When “Yes” is determined in step S11 (that is, when there is no paper), the control unit 6 determines the horizontal size of the paper P from the position of the paper sensor 7 when the operation is turned on (step S12), and then After the paper sensor 7 is switched to the operation-off state, the paper size determination process is finished (step S13). In step S12, the control unit 6 determines that the horizontal size of the paper P is 431.8 mm, for example, when the position of the paper sensor 7 is X14_R2 when the operation is turned on (see FIG. 5).
On the other hand, if “No” in step S11 (that is, if there is a sheet), the control unit 6 immediately switches the sheet sensor 7 to the operation-off state and then returns to the process of step S8 (step S14).

 As described above, according to the present embodiment, the paper sensor 7 is switched to the operation-on state only when necessary during automatic paper size determination, so that power consumption during automatic paper size determination can be reduced. It becomes.

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 (3)

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;
Control means for switching the paper sensor to an operation-on state or an operation-off state according to the position of the paper sensor obtained from the output signal of the position sensor;
The control means turns on the paper sensor only at the position of the paper sensor at two intersections between the paper and the trajectory set in advance for each paper size, and an output signal of the paper sensor obtained at that time An image forming apparatus that determines the size of the paper based on the image.   The control means determines the size of the paper from the position of the paper sensor when the paper sensor is turned on when the output signal of the paper sensor obtained when the paper sensor is turned on indicates that paper is present. When the paper sensor is turned off later, and the output signal of the paper sensor obtained when the paper sensor is turned on indicates that there is no paper, the paper sensor is turned off immediately. The image forming apparatus according to claim 1.   3. The sheet sensor moving unit according to claim 1, wherein the sheet sensor moving unit 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. Image forming apparatus.

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