JP2021011370A - Image forming device - Google Patents

Abstract

To accurately detect the size of a paper by taking "a static error" and "a dynamic error" into consideration.SOLUTION: An image forming device includes a paper feeding tray 83 on which paper P is stacked, a side regulating plate 82 that regulates a position of an end portion of the paper P stacked on the paper feeding tray 83, a paper width sensor 101 that detects the position of the end portion of the paper P regulated by the side regulating plate 82, and outputs voltage according to the position of the end portion, and a CPU 106 that corrects the width of the paper calculated on the basis of the voltage output from the paper width sensor 101, on the basis of difference between the calculated width of the paper P and the width of the paper P stacked on the paper feeding tray 83, thereby obtaining the width of the paper P stacked on the paper feeding tray 83.SELECTED DRAWING: Figure 16

Description

The present invention relates to an image forming apparatus, and particularly to a paper width detecting apparatus.

Various sizes of paper are used in the image forming apparatus. The paper feed tray in which the paper of the image forming apparatus is stored is equipped with a paper width detecting device that detects the size of the paper. Regarding a method for detecting the width of paper used in a paper width detecting device, for example, Patent Document 1 proposes the following method. That is, the position of the regulating member that regulates the position of the paper placed on the paper feed tray is transmitted to the variable resistor via the rack member or the pinion gear, and the resistance value of the variable resistor is transmitted according to the position of the regulating member. To change. Then, a method of detecting the width of the paper by converting the resistance value of the variable resistor into the width of the paper based on the voltage corresponding to the resistance value of the variable resistor according to the position of the regulating member has been proposed. ..

JP-A-11-130271

However, in the configuration shown in Patent Document 1 described above, the position of the paper regulating member for aligning the edges of the paper stored in the paper feed tray is transmitted to the variable resistor via the rack member or the pinion gear. , There are the following issues. The first issue is an error due to component tolerances. The conversion formula that converts the resistance value of the variable resistor to the size (width) of the paper is set so that the amount of change in the resistance value with respect to the dimensions of the intervening parts and the movable amount of the variable resistor is the optimum value in the design. It is common that it is done. Therefore, an error occurs in the paper width of the paper obtained based on the conversion formula due to the dimensional tolerance of the intervening parts and the tolerance of the change amount of the resistance value with respect to the movable amount of the variable resistor. Since the error due to the component tolerance is an error element peculiar to each component, which does not depend on the operation of the intervening component or the variable resistor, it is referred to as "static error" below. The second issue is the error due to the free running of parts. Even though the paper regulation member is moving due to backlash when assembling the intervening parts, backlash of the meshing gears, bending of the parts due to the force applied to the paper regulation member, etc., the movement of the variable resistor However, the resistance value of the variable resistor does not change, causing backlash. The idle running of such intervening parts causes an error in the detected paper width. Since the error due to the free running of the component is a dynamic error element caused by the operation of the intervening component, it is referred to as "dynamic error" below.

The present invention has been made under such circumstances, and an object of the present invention is to accurately detect the size of paper in consideration of "static error" and "dynamic error".

In order to solve the above-mentioned problems, the present invention includes the following configurations.

(1) An image forming apparatus including a control means for controlling image formation on paper, which includes a loading portion on which the paper is loaded and a regulating portion that regulates the position of an end portion of the paper loaded on the loading portion. , Calculated based on the detection means that detects the position of the edge of the paper regulated by the regulation unit and outputs a detection signal according to the position of the edge, and the detection signal output from the detection means. The width of the paper loaded on the loading unit is obtained by correcting the width of the calculated paper based on the difference between the calculated width of the paper and the width of the paper loaded on the loading unit. An image forming apparatus comprising: a control means.

According to the present invention, the size of paper can be detected with high accuracy by adding "static error" and "dynamic error".

Sectional drawing which shows the structure of the image forming apparatus of an Example A perspective view showing the configuration of the paper width sensor and the printed circuit board of the embodiment. A perspective view for explaining the relationship between the configuration of the paper width detection unit of the embodiment and the side regulation plate. Sectional drawing explaining the relationship between the structure of the paper width detection unit of an Example and a side regulation plate A perspective view illustrating the relationship between the paper width detection unit and the side regulation plate of the embodiment. The figure explaining the operation of the paper width detection unit of an Example The figure explaining the operation of the paper width sensor of an Example The figure explaining the relationship between the angle of the protrusion shaft part of the paper width sensor of an Example, and the paper width. The figure which shows the error between the output voltage of the paper width sensor of an Example, and the actual paper width. The figure explaining the dynamic error of the paper width sensor of an Example The figure explaining the system configuration which detects the paper width of an Example The figure which shows the error between the AD conversion value of the output voltage of the paper width sensor of an Example, and the actual paper width. The figure which shows the error between the AD conversion value of the output voltage of the paper width sensor of an Example, and the actual paper width. The figure explaining the correction process of an Example The figure explaining the correction process of an Example The figure explaining the correction process of an Example The figure explaining the correction process of an Example The figure explaining the structure of the paper width detection unit of another Example

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The dimensions, materials, shapes, etc. of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions, and the present invention It is not intended to limit the scope of the above to the following embodiments.

[Configuration of image forming apparatus]
First, the overall configuration of the image forming apparatus to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a laser beam printer 1 (hereinafter, referred to as a printer 1) which is an aspect of the image forming apparatus of this embodiment. In the printer 1 shown in FIG. 1, a paper feeding unit 80 for accommodating paper P, which is a recording material, is arranged at the bottom. The paper feed unit 80 is provided with a paper feed tray 83, and the user can directly load the paper P. In the drawing of the paper feed unit 80, the registration roller 51 that aligns the tip position of the paper P conveyed from the paper feed unit 80 and conveys the paper P to the transfer roller 91 and the registration facing roller are in the upper left portion. 52 is arranged. Hereinafter, the registration roller 51 is referred to as a registration roller 51, and the registration facing roller 52 is referred to as a registration facing roller 52.

At the upper part of the paper feed unit 80 in the drawing, there is a paper width detection unit 100 that detects a width orthogonal to the transport direction of the paper P (the direction from right to left in the figure), and a static photosensitive drum 11. A laser scanner unit 30 that forms an electro-latent image is arranged. A scanner frame 31 is arranged on the left side of the drawing of the laser scanner unit 30, and the laser scanner unit 30 is fixed to the scanner frame 31. The process cartridge 10 is arranged in the left direction of the scanner frame 31 in the drawing. The process cartridge 10 is exposed by a light beam emitted from the laser scanner unit 30 according to image information to develop a photosensitive drum 11 on which an electrostatic latent image is formed and an electrostatic latent image on the photosensitive drum 11. It has a developing device (not shown) that forms a toner image. A transfer roller 91 for transferring the toner image on the photosensitive drum 11 to the paper P is provided in the left direction of the process cartridge 10 at a position facing the process cartridge 10. Further, a fixing unit 20 for fixing the toner image transferred to the paper P to the paper P is arranged in the upper part of the drawings of the process cartridge 10 and the transfer roller 91. An output roller pair 61 for discharging the paper P conveyed from the fixing unit 20 to the output tray 65 is provided in the upper right portion of the drawing of the fixing unit 20. Further, a control unit (not shown) that controls image formation on the paper P is equipped with CPU 106 (see FIG. 11), which is a control means, and collectively controls the image formation operation of the printer 1. ..

Further, the printer 1 of this embodiment has a document transporting unit 130 and a document reading unit 120 at the upper part of the apparatus, and includes a reading device 110 for reading a document. Further, on the side surface of the document reading unit 120, a keypad for the user to input data to the printer 1 and an operation unit 109 having a display unit for displaying various information are provided.

In the document transfer unit 130 of the reading device 110, the documents placed on the document table 131 are transported one by one to the document table 126 of the document reading unit 120 by the paper feed roller 132. The document is driven by the motor 136 and is conveyed to a predetermined position on the platen 126 by the rotating document transfer belt 137, and the document is read by the document reading unit 120. When the reading of the document is completed, the flapper 135 changes the transfer path of the document, the motor 136 is reversed, and the document transfer belt 137 is rotated in the opposite direction, so that the document is ejected to the ejection tray 138. Further, the document stand 131 includes a document regulating plate 139 that regulates an end portion in a width direction orthogonal to the document transport direction, and a document width detection unit 140 that detects a width that is a length orthogonal to the document transport direction. Is provided.

In addition, the document reading unit 120 reads the document image on the document table 126 with the following configuration. The exposure lamp 122 installed on the first mirror base 121 illuminates the document on the platen 126 while moving in the longitudinal direction (left-right direction in the drawing) of the document. The scattered light from the document due to the irradiation of the exposure lamp 122 is reflected by the mirrors of the first mirror base 121 and the second mirror base 123 and reaches the lens 124. The first mirror base 121 and the second mirror base 123 are driven by the motor 125 and move. The image on the manuscript is imaged on the light receiving portion of the CCD line sensor 127 via the first mirror base 121, the second mirror base 123, and the lens 124, and is photoelectrically converted by the CCD line sensor 127. The photoelectrically converted signal is processed by the signal processing unit 128 and output to the CPU 106 described above.

[Image formation operation]
First, the user sets the paper P in the paper feed tray 83, which is a loading unit for loading the paper P in FIG. 1, in order to form an image on the paper P. At this time, the user moves (slides) the side regulation plates 82 (82R, 82L), which is a regulation unit that regulates the size in the width direction orthogonal to the transport direction of the paper P, to a position corresponding to the width of the paper P. ..

When a print job composed of print commands, image information, etc. is input from an external host computer (not shown) or the like to the CPU 106 of the control unit, the printing operation on the paper P is started. Under the control of the CPU 106, first, the paper P is fed from the paper feed tray 83 by the feed roller 81, and is conveyed to the cash register roller 51 and the cash register facing roller 52. Further, the CPU 106 controls the laser scanner unit 30 based on the image information in parallel with the transfer control of the paper P to form an electrostatic latent image on the photosensitive drum 11 and control the developing device (not shown). Then, a toner image is formed on the photosensitive drum 11. Then, the CPU 106 rotates the registration roller 51 and the registration facing roller 52 in accordance with the timing when the toner image formed on the photosensitive drum 11 moves to the transfer roller 91, and conveys the paper P to the transfer roller 91. As a result, the paper P is conveyed to the nip portion formed by the contact between the photosensitive drum 11 and the transfer roller 91, and the toner image on the photosensitive drum 11 is transferred to the paper P at the nip portion. The toner image transferred to the paper P is melt-fixed on the paper P by being heated and pressurized by the fixing unit 20 composed of a fixing roller or the like. Then, the paper P after the toner image is fixed is ejected to the output tray 65 by the output roller pair 61, and the image forming operation is completed.

[Paper width sensor configuration]
In FIG. 2, in the paper width detection unit 100 shown in FIG. 1, a paper width sensor 101 (hereinafter referred to as a width sensor 101) for detecting the width of the paper P housed in the paper feed tray 83 and a width sensor 101 are mounted. It is a perspective view which shows the structure of the printed circuit board 105. As shown in FIG. 2, the width sensor 101, which is a detection means, is composed of a protrusion shaft portion 101a and a sensor main body 101b. The protrusion shaft portion 101a is provided with a hole portion in the center, and is rotatably attached to the sensor main body 101b. On the other hand, the sensor body 101b is a rotary variable resistor, and is fixed to the printed circuit board 105 in a state of being electrically connected. The resistance value of the sensor body 101b changes according to the rotation angle of the protrusion shaft portion 101a. The width sensor 101 converts the resistance value of the variable resistor of the sensor main body 101b into a voltage which is a detection signal and outputs it to the CPU 106 (see FIG. 11) of the control unit (not shown).

[Paper width detection unit configuration]
FIG. 3 is a perspective view illustrating the relationship between the configuration of the paper width detection unit 100 and the side regulation plate 82 (82R). FIG. 3A is a perspective view of the paper width detection unit 100 and the side regulation plate 82 (82R) when viewed from the downstream side of the paper P of the paper feed tray 83 in the paper transport direction. As shown in FIG. 3A, the printed circuit board 105 to which the width sensor 101 is attached is attached to the size detection holder 102 that moves in conjunction with the movement of the side regulation plate 82 (82R). That is, the printed substrate 105 is fed in a direction in which the center line S (indicated by the alternate long and short dash line) of the protrusion shaft portion 101a of the width sensor 101 is substantially perpendicular to the gravity direction (in the figure, the arrow G direction). The paper P housed in the tray 83 is arranged so as to be substantially orthogonal to the paper transport direction. Further, on the opposite side of the surface of the printed circuit board 105 to which the width sensor 101 is attached, a sensor gear 103 that rotates according to the movement of the side regulation plate 82 (82R) is provided.

FIG. 3B is a perspective view of the paper width detection unit 100 and the side regulation plate 82 (82R) when viewed from the upstream side of the paper P of the paper feed tray 83 in the paper transport direction. As shown in FIG. 3B, a sensor gear 103 is attached to the surface of the printed circuit board 105 on the opposite side of the width sensor 101. The sensor gear 103 has a rotation shaft 103a (not shown in FIG. 3B), is fitted into a hole provided in the protrusion shaft portion 101a of the width sensor 101, and is rotatably attached to the size detection holder 102. ing. The sensor rack 104 is connected to the side regulation plate 82R (first regulation member) via the protrusion 82Ra. Then, when the paper P is stored in the paper feed tray 83, if the side regulation plate 82R is slid according to the width of the paper P, the sensor rack 104 also slides in conjunction with the movement of the side regulation plate 82R. It has become. For example, when the side regulation plate 82R is moved in the A direction in the drawing, the sensor rack 104 also slides in the A direction, and the sensor gear 103 rotates in the Z direction in the drawing. On the other hand, when the side regulation plate 82R is moved in the B direction in the drawing, the sensor rack 104 also slides in the B direction, and the sensor gear 103 rotates in the Y direction in the drawing.

FIG. 4 is a cross-sectional view illustrating the relationship between the configuration of the paper width detection unit 100 and the side regulation plate 82 (82R). FIG. 4 shows the cut surfaces of the paper width detection unit 100 and the side regulation plate 82R when viewed from the right side to the left side in FIG. 3B when the sensor gear 103 is cut so as to include the center of the rotation shaft 103a. Shown. As shown in FIG. 4, the printed circuit board 105 is fixed to the size detection holder 102. Further, one end of the rotating shaft 103a of the sensor gear 103 is rotatably supported by the size detection holder 102, and the other end is fitted into a hole provided in the protruding shaft portion 101a of the width sensor 101 attached to the printed circuit board 105. Has been done. As a result, the protrusion shaft portion 101a also rotates in the Y direction and the Z direction shown in FIG. 3B in conjunction with the rotation of the rotation shaft 103a of the sensor gear 103. Further, the side regulation plate 82R is connected to the sensor rack 104 via a protrusion 82Ra of the side regulation plate 82R. Further, the sensor rack 104 is attached to the size detection holder 102 so as to transmit the movement (movement) of the side regulation plate 82R to the sensor gear 103. As a result, the sensor rack 104 can also move in the A and B directions in conjunction with the movement of the side regulation plate 82R in the directions A and B shown in FIG. 3 (b) orthogonal to the paper transport direction in the drawing. ing.

FIG. 5 is a perspective view of the paper width detection unit 100 as viewed from the paper feed tray 83 side. As shown in FIG. 5, a groove portion 104a for fitting with the protrusion 82Ra of the side regulation plate 82R is provided in the lower portion of the sensor rack 104. On the other hand, as shown in FIG. 3B, a protrusion 82Ra is provided on the side of the side regulation plate 82R facing the sensor rack 104, and the side regulation plate 82R is fitted with the groove portion 104a and the protrusion 82Ra to regulate the side. The plate 82R and the sensor rack 104 are connected. As a result, the sensor rack 104 is configured to be movable in synchronization with the movement of the side regulation plate 82R. Further, as shown in FIG. 5, the gear provided on the sensor gear 103 is meshed with the teeth provided on the sensor rack 104. Therefore, when the sensor rack 104 moves in synchronization with the movement of the side regulation plate 82R, the sensor gear 103 also rotates in conjunction with the movement of the sensor rack 104.

[Operation of paper width detection unit]
FIG. 6 is a diagram illustrating the operation of the paper width detection unit 100 when the paper P is set in the paper feed tray 83. FIG. 6 is a view of the configuration of the paper feed tray 83 and the paper width detection unit 100 shown in FIG. 1 when viewed from the right side to the left side of FIG. In FIG. 6, the user moves the side regulation plate 82R to the right in the drawing in order to set the paper P in the paper feed tray 83. Then, when the paper P is set in the paper feed tray 83, the user moves the side regulation plate 82R in the direction of the arrow A to a position where the paper P comes into contact with the width side end portion of the paper P. The side regulation plate 82 has a pair of left and right sides of 82R (right side) and 82L (left side), and when one is slid, the other is symmetrically slid by a pinion (not shown). Therefore, the left and right edges of the paper P in the width direction can be regulated at the same time.

In FIG. 6, when the side regulation plate 82R is slid (moved) in the direction of arrow A, the side regulation plate 82L (second regulation member) slides in the slide direction of the side regulation plate 82R in conjunction with the movement of the side regulation plate 82R. It slides in the B direction, which is a direction symmetrical to the (operation direction). At this time, when the side regulation plate 82R moves in the A direction, the sensor rack 104 connected to the side regulation plate 82R via the groove portion 104a and the protrusion 82Ra also moves in the arrow A direction. Then, as the sensor rack 104 moves in the direction of arrow A, the sensor gear 103 whose gears mesh with the teeth provided on the sensor rack 104 rotates in the direction of arrow Z. As a result, the protrusion shaft portion 101a (not shown in FIG. 6) of the width sensor 101 (not shown in FIG. 6) to which the rotation shaft 103a (not shown in FIG. 6) of the sensor gear 103 is fitted also rotates in the arrow Z direction. To do. The width sensor 101 converts the resistance value of the variable resistor of the sensor main body 101b according to the angle of the protrusion shaft portion 101a into a voltage and outputs it to the CPU 106 (see FIG. 11) of the control unit (not shown).

[Paper width sensor operation]
(When there is no static error or dynamic error)
Next, the ideal operation of the paper width detection unit 100 will be described. Here, the "ideal operation" is an operation when there is no "static error" which is an error due to the above-mentioned component tolerance and "dynamic error" which is an error due to idle running of the component.

FIG. 7A is a graph showing the relationship between the angle of the protrusion shaft portion 101a of the width sensor 101 and the width of the paper P. In FIG. 7A, the horizontal axis represents the angle (unit: °) of the protruding shaft portion 101a, and the vertical axis corresponds to the output voltage (unit: V (volt)) of the width sensor 101 and the output voltage. The paper width (paper type and width of paper P) is shown. From FIG. 7A, it can be seen that as the angle of the protrusion shaft portion 101a increases, the resistance value of the variable resistor also increases, and the output voltage of the width sensor 101 also increases in proportion to this. In this embodiment, when the angle of the protrusion shaft portion 101a is 30 °, the width of the paper P is A6 size (105 mm), and when the angle is 330 °, the width of the paper P is A4 size (210 mm). The output voltage is set to. By linearly changing the angle of the protrusion shaft portion 101a in this way, the width of the paper P can also be detected linearly.

7 (b) to 7 (d) are diagrams showing the state of the protrusion shaft portion 101a of the width sensor 101 when the angles of the protrusion shaft portion 101a are 30 °, 180 °, and 330 °, respectively. The paper P shown in FIG. 6 has an A6 size, and the state of the protrusion shaft portion 101a of the width sensor 101 is the position shown in FIG. 7B. In FIG. 6, when the side regulation plate 82R is adjusted to the width of the paper P, the angle of the protrusion shaft portion 101a is 30 °, and when converted to the paper width, it is 105 mm, which is the width of the A6 size. When the side regulation plate 82R is slid in the direction of arrow B (rightward) from the state of FIG. 6, the angle of the protrusion shaft portion 101a increases according to the amount of slide, and FIGS. 7 (b) to 7 (d). ). Along with this, the voltage output from the width sensor 101 corresponding to the angle of the protrusion shaft portion 101a also increases, and the width of the paper P detected by the CPU 106 also increases.

In FIG. 7A, the output voltage is not displayed in the section where the angle of the protrusion shaft portion 101a is 0 ° to 20 ° and the section where the angle is 340 ° to 360 °. This is because the width sensor 101 is out of the use area due to its electrical characteristics. FIG. 7E is a diagram illustrating a configuration of a variable resistor inside the width sensor 101. The width sensor 101 has a resistor that is a resistor inside, and a rotating electrode that rotates according to the angle of the protruding shaft portion 101a of the width sensor 101 in which the rotating shaft 103a of the sensor gear 103 is fitted. .. Then, the width sensor 101 outputs a voltage of 0 V (GND) when the angle of the rotating electrode is 20 °, and outputs a voltage of 3.3 V when the angle of the rotating electrode is 340 °. In the width sensor 101, the actual use angle of the rotating electrode is the angle in the section of 30 ° to 330 ° (= 360 ° −30 °). Further, in the width sensor 101, the use limit angles in terms of electrical characteristics are 20 ° and 340 ° (= 360 ° -20 °), and when the angle of the rotating electrode is less than 20 ° and exceeds 340 °. Does not output voltage.

Therefore, in FIG. 7A, the angle of the protrusion shaft portion 101a corresponding to the minimum width of the paper P that can be detected by the width sensor 101 is set to 30 °, and the angle is set to 20 ° outside the use area due to the electrical characteristics of the width sensor 101. On the other hand, a mechanical margin of 10 ° is provided. Similarly, for the maximum width of the paper P, the angle of the protrusion shaft portion 101a corresponding to the maximum width of the paper P that can be detected by the width sensor 101 is set to 330 °, and the angle is 340 ° outside the used area due to the electrical characteristics of the width sensor 101. On the other hand, a mechanical margin of 10 ° is provided.

As described above, when one of the side regulation plates 82R and 82L is slid, the other is also interlocked and slides symmetrically. Therefore, the slide amount N of the side regulation plates 82R and 82L is less than half of the difference value obtained by subtracting the minimum width from the maximum width of the paper P detected by the width sensor 101. Further, this slide amount N corresponds to the slide amount of the sensor rack 104.

Here, the pitch circumference length of the sensor gear 103 is set to a value obtained by combining the slide amount N with an arc corresponding to an angle (20 °) outside the used area on the electrical characteristics of the width sensor 101. For example, if the maximum width of the paper P is 210 mm of A4 size and the minimum width is 105 mm of A6 size as set in FIG. 7A, N is 52.5 mm (= (210 mm-105 mm) / 2). Further, since the rotation angle 300 ° (= 330 ° -30 °) of the sensor gear 103 corresponds to 52.5 mm, the pitch circumference length of the sensor gear 103 is 63 mm (= 52.5 mm × (360 ° / 300 °)). That is all. Assuming that the module of the sensor gear 103 is 1, the number of teeth is set to 21 or more.

(If there are static and dynamic errors)
Subsequently, the operation of the paper width detection unit 100 when there is a "static error" and a "dynamic error" will be described. FIG. 8 is a graph of the angle of the protrusion shaft portion 101a and the output voltage of the width sensor 101 when there are “static error” and “dynamic error” in the graph of FIG. 7 described above (in gray in the figure). Display) is added. In FIG. 8, the “ideal straight line” shows the relationship between the angle of the protrusion shaft portion 101a and the output voltage of the width sensor 101 in the absence of the “static error” and the “dynamic error” described in FIG. Pointing to a linear graph. On the other hand, the graph showing the range in which the output voltage can be taken, which is described as "actual characteristics" in FIG. 8, is a protrusion when there are "static error" and "dynamic error". The relationship between the angle of the shaft portion 101a and the output voltage of the width sensor 101 is shown. In the graph showing the "actual characteristics", even if the angle of the protrusion shaft portion 101a is the same, the output voltage of the width sensor 101 is different due to the "dynamic error" as described later. Further, as will be described later, the output voltage has an error different from the output voltage in the case of an ideal straight line depending on the direction in which the side regulation plate 82 is slid.

FIG. 9 is a graph obtained by converting the graph of FIG. 8 for the sake of simplicity. The vertical axis shows the amount of deviation from the output voltage in the ideal straight line, that is, the error of the output voltage, and the horizontal axis shows the width sensor 101. It shows the output voltage. The graph shown in FIG. 9 is composed of two curves. One is to move the side regulation plate 82 from the maximum width side of the paper P (the output voltage of the width sensor 101 is 3.3V side) to the minimum width side (the output voltage is 0V side) between the side regulation plates 82R and 82L. It is a curve when it is moved in the direction of narrowing the distance (the curve drawn on the lower side in the figure). The other curve is when the side regulation plate 82 is moved from the minimum width side (0V side) of the paper P to the maximum width side (3.3V side) in the direction of increasing the distance between the side regulation plates 82R and 82L. The curve (the curve drawn on the lower side in the figure). The two curves have almost the same shape and are translated in the vertical direction in the figure. Further, the gray area sandwiched between the two curves indicates the area of the output voltage error that the two curves can take. In FIG. 9, the true paper width is wide, but the detected paper width is narrow, that is, the output voltage in the “ideal straight line” in FIG. 8 is larger than the output voltage in the “actual characteristics”. The error is in the + (plus) direction. On the other hand, in FIG. 9, the true paper width is narrow, but the detected paper width is wide, that is, the output voltage in the “ideal straight line” in FIG. 8 is smaller than the output voltage in the “actual characteristics”. The error is in the- (minus) direction.

In FIG. 9, the difference between the peak and the bottom of the valley of each curve is the above-mentioned “static error” (in FIG. 9, the “static error” in the upper curve is shown). The "static error" is caused by the dimensional tolerance of the intervening component and the tolerance of the amount of change in the resistance value with respect to the movable amount of the variable resistor. On the other hand, the amount of parallel movement of the two curves shown in FIG. 9 in the vertical direction is the above-mentioned "dynamic error". The reason why the variable resistor of the width sensor 101 does not move even though the side regulation plate 82 is slid is as follows. That is, the gap which is the assembly backlash between each component intervening to transmit the movement (slide) of the side regulation plate 82 to the variable resistor, the backlash of the meshing gear, and the force applied to the side regulation plate 82. This is due to the bending (deformation) of each part due to. As a result, even though the side regulation plate 82 is slid, the movement of the side regulation plate 82 is not transmitted to the variable resistor, and the variable resistor of the width sensor 101 does not move, resulting in "idle running". The "dynamic error" is caused by the idling of these intervening components.

Next, the "dynamic error" will be described with reference to the figure. In FIG. 10, the side regulation plate 82 is moved in a direction in which the distance between the side regulation plates 82R and 82L is narrowed from the maximum width side (3.3V side) of the paper P, and the protrusion shaft portion 101a is at an angle A °. It is a graph when it is inverted in the direction which widens the space between side regulation plates 82R and 82L. The vertical axis and the horizontal axis of FIG. 10 are the same as those of FIG. 9, and the description thereof will be omitted here. When the side regulation plate 82 is slid in the direction of narrowing the distance between the side regulation plates 82R and 82L, the backlash of the intervening parts, the backlash of the meshing gears, the bending of the parts due to the force applied to the side regulation plate 82, etc. , It is in a state of hitting in one direction. However, at the position of the angle A °, contrary to the previous case, the side regulation plate 82 starts to slide in the direction of widening the distance between the side regulation plates 82R and 82L. Then, the backlash of the intervening parts that are in contact with each other in one direction, the backlash of the meshing gears, and the bending of the parts due to the force applied to the side regulation plate 82 are temporarily released. Then, when the distance between the side regulation plates 82R and 82L is widened, the backlash of the intervening parts, the backlash of the meshing gears, the bending of the parts due to the force applied to the side regulation plate 82, etc. are opposite to those before. It will be in a state of hitting in the direction. During this time, the side regulation plate 82 and the intervening parts are moving, but the movement is not transmitted to the variable resistor of the width sensor 101 and idle running occurs, and as a result, the protrusion shaft portion 101a remains at an angle of A °. It does not change. At this time, although the distance between the side regulation plates 82R and 82L changes in the expanding direction, the angle of the protrusion shaft portion 101a of the width sensor 101 remains unchanged at the angle A °. Therefore, the error between the output voltage of the width sensor 101 output according to the angle of the protrusion shaft portion 101a and the output voltage placed on the ideal straight line increases in the + direction. Further, the output voltage of the width sensor 101 is output to the CPU 106 (see FIG. 11) of the control unit (not shown), and the CPU 106 does not change the output voltage of the width sensor 101, so that the paper width of the paper P remains narrow. Will be falsely detected. As described above, the error when the side regulation plate 82 is operated in the direction of widening the distance between the side regulation plates 82R and 82L is the case where the side regulation plate 82 is operated in the direction of narrowing the distance between the side regulation plates 82R and 82L. Is greater than the error of.

Here, based on the graph of FIG. 10, the change in the error when the side regulation plate 82 is operated in the direction of narrowing the distance between the side regulation plates 82R and 82L having a small error from the true paper width has been described. As described above, the factors that cause an error from the true paper width are the backlash of the intervening parts, the backlash of the meshing gears, and the bending of the parts due to the force applied to the side regulation plate 82. In FIG. 10, the error from the true paper width was operated in the direction of narrowing the distance between the side regulation plates 82R and 82L when the side regulation plate 82 was operated in the direction of widening the distance between the side regulation plates 82R and 82L. It's bigger than the case. However, although the factors that cause an error from the true paper width are the same, when the error from the true paper width is operated in the direction of narrowing the distance between the side regulation plates 82R and 82L, the side regulation plates 82R and 82L are operated. It may be larger than when the operation is performed in the direction of narrowing the interval between.

[System configuration to detect paper width]
FIG. 11 is a diagram for explaining a system configuration for detecting the width of the paper P of the printer 1 of this embodiment. In FIG. 11, the CPU 106 of the control unit has a ROM and a RAM as storage devices, and uses the RAM as a work area based on various control programs stored in the ROM to collectively perform the image forming operation of the printer 1. To control. Further, in FIG. 11, the CPU 106 has three terminals, an AVref terminal, an AD terminal, and an AVss terminal. A DC voltage of 3.3 V (volt), which is the maximum value of the output voltage from the width sensor 101, is input to the AVref terminal, and is connected to the ground (GND), which is the minimum value of 0 V of the output voltage, to the AVss terminal. ing. Further, an output voltage corresponding to the angle of the protrusion shaft portion 101a of the width sensor 101 is input from the width sensor 101 of the paper width detection unit 100 to the AD terminal. The CPU 106 converts the output voltage (analog voltage) of the width sensor 101 input to the AD terminal, which is an AD conversion input port, into a digital value corresponding to the output voltage. Further, the CPU 106 is connected to the non-volatile memory 107 which is a storage means, accesses the non-volatile memory 107, and reads / writes data.

Spec value (ideal value excluding error) of the target dimension of the component intervening to transmit the movement of the side regulation plate 82 to the variable resistor of the width sensor 101 and the amount of change in the resistance value with respect to the movable amount of the variable resistor. Is known at the design stage. Therefore, the CPU 106 knows the digital value (hereinafter referred to as AD conversion value) obtained by A / D converting the paper width of the paper P from the output voltage from the width sensor 101, and the target dimensions and specification values of the parts. It can be calculated uniquely based on the mathematical formula using the parameters of. The paper width obtained by the mathematical formula in this way is referred to as "ideal paper width" here. However, the ideal paper width does not take into account the above-mentioned "static error" and "dynamic error", but adds "static error" and "dynamic error" to "true paper". It is different from "width".

[Paper width correction processing]
Subsequently, a correction process for obtaining the "true paper width" by performing correction in which "static error" and "dynamic error" are added to "ideal paper width" will be described. FIG. 12 is a graph in which the horizontal axis of the graph shown in FIG. 9 is changed from the output voltage from the width sensor 101 to an AD conversion value. In this embodiment, the resolution of the A / D conversion is 12 bits (bit), and the output voltage from 0V to 3.3V from the width sensor 101 is converted to 0 to 4095 (= 2 ¹² -1). In the graph connecting the plots marked with circles shown in FIG. 12, the side regulation plate 82 is narrowed from the maximum width side (AD conversion value 4095 side) to the minimum width side (AD conversion value 0 side) of the paper P. It is a graph connecting 20 data in the profile data when it is slid.

FIG. 13 is a graph in which the horizontal axis of the graph shown in FIG. 9 is changed from the output voltage from the width sensor 101 to an AD conversion value, as in FIG. The graph connecting the plots of the circles shown in FIG. 13 shows the side regulation plate 82 in the direction of expanding from the minimum width side (0 side of the AD conversion value) to the maximum width side (4095 side of the AD conversion value) of the paper P. It is a graph connecting 20 data in the profile data when it is slid. Although the error data of the same AD conversion value is extracted from the 20 data plotted by the circles in FIGS. 12 and 13, different AD conversion values may be extracted. Further, the number of data to be extracted is not limited to 20.

In this embodiment, data such as AD conversion values when the side regulation plate 82 is slid from the maximum width side to the minimum width side of the paper P and when the side regulation plate 82 is slid from the minimum width side to the maximum width side of the paper P is obtained. , It is assumed that it is stored in the non-volatile memory 107 in advance. Data such as AD conversion values may be stored in the non-volatile memory 107, for example, in the assembly process of the printer 1.

FIG. 14 is a graph that simply represents a graph in which the plots marked with circles shown in FIG. 12 are connected. In FIG. 12, the horizontal axis shows the AD conversion value, and the vertical axis includes the “ideal paper width” calculated based on the AD conversion value, and the “static error” and “dynamic error”. It showed an error from the "true paper width". In FIG. 14, the horizontal axis represents the AD conversion value, and the vertical axis represents the paper width of the paper P. In the figure, the straight line indicated by the dotted line is a straight line indicating the "ideal paper width" calculated based on the AD conversion value (A ₀ , A _1, etc.), and in this embodiment, the "ideal paper width" is α. It is assumed that it is obtained by the linear expression of × AD conversion value + β (note that the parameters α and β are known). On the other hand, in the figure, the curve shown by the broken line indicates the "true paper width", and the difference between the "ideal paper width" and the "true paper width" shown by the thick black straight line (H ₀ , H _1, etc.) ) Corresponds to the error on the vertical axis of FIG.

In the non-volatile memory 107 described above, the AD conversion value and the difference data (difference information) between the ideal paper width data and the true paper width data calculated based on the AD conversion value are associated with each other and first. It is stored as correction data of. Data is stored in the non-volatile memory 107 as follows. First, a plurality of representative points (for example, (n + 1)) of AD conversion values are extracted while sliding the side regulation plate 82 in the direction of narrowing the distance between the side regulation plates 82R and 82L from the state of being expanded to the maximum. Then, the extracted (n + 1) AD conversion values (A ₀ , A ₁ , ..., _An-1 , _An ) and the (n + 1) AD conversion values corresponding to the (n + 1) AD conversion values. The error data (H ₀ , H ₁ , ..., H _n-1 , H _n ) is stored in the non-volatile memory 107. Here, the error data Hn is an "ideal paper width" calculated based on the AD conversion value described above from the "true paper width" obtained by actually measuring the distance between the side regulation plates 82R and 82L. It is the value obtained by subtracting. Therefore, in FIG. 14, the errors H ₀ and H ₁ are positive values, and the error H ₂ is a negative value. As described above, the "ideal paper width" can be uniquely calculated by the linear expression of α × AD conversion value + β composed of the AD conversion value and the known parameters α and β.

FIG. 15 is a graph that simply represents a graph in which the plots marked with circles shown in FIG. 13 are connected. In FIG. 13, the horizontal axis shows the AD conversion value, and the vertical axis includes the “ideal paper width” calculated based on the AD conversion value, and the “static error” and “dynamic error”. It showed an error from the "true paper width". In FIG. 15, the horizontal axis represents the AD conversion value, and the vertical axis represents the paper width of the paper P. In the figure, the straight line shown by the dotted line is a straight line indicating the "ideal paper width" calculated based on the AD conversion value (B ₀ , B _1, etc.), and in this embodiment, the "ideal paper width" is α. It is assumed that it is obtained by the linear expression of × AD conversion value + β (note that the parameters α and β are known). On the other hand, in the figure, the curve shown by the broken line shows the "true paper width", and the difference between the "ideal paper width" and the "true paper width" shown by the thick black straight line (I ₀ , I _1, etc.) ) Corresponds to the error on the vertical axis of FIG.

In the non-volatile memory 107 described above, the AD conversion value shown in FIG. 15 and the difference data (difference information) between the ideal paper width data and the true paper width data calculated based on the AD conversion value are associated with each other. Therefore, it is stored as the second correction data. Data is stored in the non-volatile memory 107 as follows. First, a plurality of representative points (for example, (n + 1)) of AD conversion values are extracted while sliding the side regulation plate 82 in the direction of increasing the distance between the side regulation plates 82R and 82L from the state of being narrowed to the minimum. Then, the extracted (n + 1) AD conversion values (B ₀ , B ₁ , ..., B _n-1 , B _n ) and the (n + 1) (n + 1) AD conversion values corresponding to the (n + 1) AD conversion values. error data _{(I 0, I 1, ···} , I n-1, I n) and a is stored in nonvolatile memory 107. Here, the error data In is the "ideal paper width" calculated based on the AD conversion value described above from the "true paper width" obtained by actually measuring the distance between the side regulation plates 82R and 82L. It is the value obtained by subtracting. Thus, in FIG. 15, the error _I 0 ~I _n is a positive value. As described above, the "ideal paper width" can be uniquely calculated by the linear expression of α × AD conversion value + β composed of the AD conversion value and the known parameters α and β.

Next, a method in which the CPU 106 obtains the “true paper width” by using the data values stored in the non-volatile memory 107 by the above method will be described. As described above, the width sensor 101 outputs a voltage corresponding to the angle of the protrusion shaft portion 101a to the CPU 106, and the CPU 106 A / D-converts the output voltage from the width sensor 101 input to the AD terminal to obtain ". "AD conversion value" is acquired. The CPU 106 narrowed or widened the distance between the side restricting plates 82R and 82L based on whether the AD conversion value acquired in a predetermined cycle decreased or increased from the previously acquired AD conversion value. Is judged. Further, the CPU 106 calculates the ideal paper width by using the AD conversion value acquired in a predetermined cycle and the above-mentioned linear expression α × AD conversion value + β. Here, it is assumed that the linear expression α × AD conversion value + β is stored in the non-volatile memory 107 in advance, but for example, it may be built in the ROM and included in the program executed by the CPU 106. ..

Subsequently, a method of obtaining an error when the distance between the side regulation plates 82R and 82L is narrowed and widened will be described. First, a method of obtaining an error when the CPU 106 determines that the AD conversion value acquired in a predetermined cycle is smaller than the previously acquired AD conversion value, that is, the distance between the side regulation plates 82R and 82L is narrowed will be described. To do. FIG. 16 is a diagram illustrating a method of calculating an “error” based on the graph shown in FIG. In addition, "(a) AD conversion value" of FIG. 16 shows the AD conversion value acquired by CPU 106 in a predetermined cycle. In this embodiment, the AD conversion value stored in the non-volatile memory 107, the AD conversion value of two points in the vicinity sandwiching "(a) AD conversion value" among the error data corresponding to the AD conversion value, and AD The "(c) error" is calculated using the error data corresponding to the converted value. Specifically, the CPU 106 selects "(a) AD conversion value" from the AD conversion values (A ₀ , A ₁ , ..., _An-1 , _An ) stored in the non-volatile memory 107. Two AD conversion values in the vicinity to be sandwiched are determined. In FIG. 16, AD conversion values A ₃ and A ₄ correspond to each other. Next, the CPU 106 selects the error data corresponding to the determined AD conversion value from the error data (H ₀ , H ₁ , ..., H _n-1 , H _n ) stored in the non-volatile memory 107. Obtained from the non-volatile memory 107. In FIG. 16, the error data H ₃ and H ₄ correspond to the error data of the AD conversion values A ₃ and A ₄ . Then, the CPU 106 linearly interpolates the error data H ₃ and H ₄ between the AD conversion values A ₃ and A ₄ to obtain the “(c) error” in the “(a) AD conversion value”. Then, the CPU 106 adds "(c) error" to "(b) ideal paper width" calculated by using the AD conversion value acquired in a predetermined cycle and the linear expression α × AD conversion value + β. Calculate "(d) true paper width". In this way, the CPU 106 can obtain "(d) true paper width" when the distance between the side regulation plates 82R and 82L is narrowed.

Next, a method of obtaining an error when the CPU 106 determines that the AD conversion value acquired in a predetermined cycle has increased from the previously acquired AD conversion value, that is, the distance between the side regulation plates 82R and 82L has increased will be described. To do. FIG. 17 is a diagram illustrating a method of calculating an “error” based on the graph shown in FIG. In addition, "(a) AD conversion value" of FIG. 17 shows the AD conversion value acquired by CPU 106 in a predetermined cycle. In this embodiment, the AD conversion value stored in the non-volatile memory 107, the AD conversion value of two points in the vicinity sandwiching "(a) AD conversion value" among the error data corresponding to the AD conversion value, and AD The "(c) error" is calculated using the error data corresponding to the converted value. Specifically, the CPU 106 selects "(a) AD conversion value" from the AD conversion values (B ₀ , B ₁ , ..., B _n-1 , B _n ) stored in the non-volatile memory 107. Two AD conversion values in the vicinity to be sandwiched are determined. In FIG. 17, AD conversion values B ₃ and B ₄ correspond to each other. Next, CPU 106, the error data stored in the nonvolatile memory _{107 (I 0, I 1,} ···, I n-1, I n) from among the error data corresponding to the determined AD conversion value Obtained from the non-volatile memory 107. In FIG. 17, the error data I ₃ and I ₄ correspond to the error data of the AD conversion values B ₃ and B ₄ . Then, the CPU 106 linearly interpolates the error data I ₃ and I ₄ between the AD conversion values B ₃ and B ₄ to obtain the “(c) error” in the “(a) AD conversion value”. Then, the CPU 106 adds "(c) error" to "(b) ideal paper width" calculated by using the AD conversion value acquired in a predetermined cycle and the linear expression α × AD conversion value + β. Calculate "(d) true paper width". In this way, the CPU 106 can obtain "(d) true paper width" when the distance between the side regulation plates 82R and 82L is widened.

As described above, the movement of the side regulation plate 82 is not transmitted to the width sensor 101 due to the backlash of the intervening parts, the backlash of the meshing gears, the bending of the parts due to the force applied to the side regulation plate 82, and the protrusion shaft portion. "Backlash" occurs in which the angle of 101a does not change. The "dynamic error" is caused by the idle running of these intervening parts, and the amount of the "dynamic error" is whether the side regulation plate 82 moves in the direction in which the distance between the side regulation plates 82R and 82L becomes narrower. Or it depends on whether it moves in the direction of spreading. In this embodiment, the CPU 106 determines whether the side regulation plate 82 has moved in the direction in which the distance between the side regulation plates 82R and 82L has narrowed or has moved in the direction in which the distance between the side regulation plates 82R and 82L has widened. Then, the CPU 106 performs correction processing based on the AD conversion value and the error data stored in the non-volatile memory 107 selected according to the direction in which the side regulation plate 82 moves, and calculates the true paper width.

Then, the CPU 106 changes the image formation conditions of the printer 1 based on the calculated true paper width. The image formation condition referred to here is a secondary processing condition of the image image such as the width of the image image and the enlargement / reduction ratio of the image image. The image formation conditions in the printer 1 of this embodiment are, for example, the process speed of image formation in the process cartridge 10 and the output voltage value of a power supply device (not shown) that supplies a high voltage to a developing device or the like for image formation. , Set temperature at the time of image formation of the fixing unit 20 and the like. When paper is loaded in the paper feed tray, the CPU 106 displays (notifies) the paper information set in the display device of the operation unit 109 based on the paper width information detected by the paper width detection device. Is done.

As described above, according to the present embodiment, the size of the paper can be detected with high accuracy by adding the "static error" and the "dynamic error".

[Other Examples]
(Paper width detection unit configuration)
In the above-described embodiment, as shown in FIG. 3, the width sensor 101 is arranged so as to be orthogonal to the paper P placed on the paper feed tray 83, but the width sensor 101 is parallel to the paper P. The configuration may be arranged in. FIG. 18 is a perspective view illustrating the relationship between the configuration of the paper width detection unit 100 in which the width sensor 101 is arranged in parallel with the paper P placed on the paper feed tray 83 and the side regulation plate 82 (FIG. 18 (a). )) And a top view (FIG. 18 (b)).

In FIG. 18, the paper width detection unit 100 is composed of a printed circuit board 105 to which a width sensor 101 is attached and a sensor gear 103. The printed circuit board 105 is attached to the size detection holder 102. In the above-described embodiment, the width sensor 101 is attached to the surface of the printed circuit board 105 opposite to the sensor gear 103 via the printed circuit board 105, but in FIG. 18, the width sensor 101 is attached to the printed circuit board 105 and the sensor gear. The difference is that it is provided between the 103 and the 103. As shown in FIG. 18, the width sensor 101 is installed in parallel on the upper surface of the paper P (not shown in FIG. 18) placed between the side regulation plate 82L and the side regulation plate 82R.

Similar to the above-described embodiment, when the paper P is stored in the paper feed tray 83, if the side regulation plate 82R is operated according to the width of the paper P, the sensor rack 104 is interlocked with the movement of the side regulation plate 82R. Is also connected to the side regulation plate 82R so as to slide. For example, when the side regulation plate 82R is slid to the right in FIG. 18B, the sensor rack 104 also slides to the right, and the sensor gear 103 rotates counterclockwise in the drawing. On the other hand, when the side regulation plate 82R is slid to the left in FIG. 18B, the sensor rack 104 also slides to the left, and the sensor gear 103 rotates clockwise in the drawing. Then, the sensor gear 103 has a rotation shaft and is fitted into a hole provided in the protrusion shaft portion of the width sensor 101, as in the above-described embodiment. The width sensor 101 rotates according to the rotation of the sensor gear 103, and outputs an output voltage according to the rotation angle to the CPU 106. The CPU 106 accurately detects the width size of the paper P placed on the paper feed tray 83 based on the AD conversion value obtained by converting the output voltage from the width sensor 101 and the correction data stored in the non-volatile memory 107. can do.

(Original reader)
In the above-described embodiment, the CPU 106 determines the paper width of the paper P placed on the paper feed tray 83 of the printer 1 based on the detection value of the width sensor 101 of the paper width detection unit 100, and determines the image formation conditions. An embodiment of setting and the like has been described. As described above, the printer 1 includes a reading device 110 that reads a document. Then, the document stand 131 of the scanning device 110 is orthogonal to the document restricting plate 139 that regulates the end portion in the width direction of the document and the document transporting direction, similarly to the side regulating plate 82 and the paper width detecting unit 100. A document width detection unit 140 for detecting the width is provided. Therefore, the CPU 106 can detect the width of the document placed on the document stand 131 by performing the same control as in the above-described embodiment by using the document control plate 139 and the document width detection unit 140. it can. Then, when printing the read original image on the paper P placed on the paper feed tray 83, the CPU 106 sets the image formation conditions using the information of the paper width detected by the original width detection unit 140. And can perform printing operations.

As described above, according to the other embodiments, the size of the paper can be detected with high accuracy by adding the "static error" and the "dynamic error".

P Paper 82 Side regulation plate 83 Paper tray 101 Paper width sensor 106 CPU

Claims (12)

An image forming apparatus including a control means for controlling image formation on paper.
The loading section where the paper is loaded and
A regulation unit that regulates the position of the edge of the paper loaded on the loading unit,
A detection means that detects the position of the end portion of the paper regulated by the regulation unit and outputs a detection signal according to the position of the end portion.
By correcting the width of the paper calculated based on the detection signal output from the detection means based on the difference between the calculated width of the paper and the width of the paper loaded on the loading unit. , The control means for obtaining the width of the paper loaded on the loading unit, and
An image forming apparatus comprising. Has a storage means to store information
The difference is a difference calculated in advance from the width of the paper calculated based on the detection signal output from the detection means and the measured width of the paper loaded on the loading unit, and is the detection signal. The image forming apparatus according to claim 1, wherein the image forming apparatus is stored in the storage means in association with the value of. The control means reads out the values of the two detection signals sandwiching the values of the detection signals output from the detection means and the differences associated with the two detection signals from the storage means, and detects the detection. The image according to claim 2, wherein the difference according to the value of the detection signal output from the detection means is calculated by linearly interpolating according to the value of the detection signal output from the means. Forming device. The control means obtains the width of the paper loaded on the loading unit by adding the difference corresponding to the calculated value of the detection signal to the width of the paper calculated based on the detection signal. The image forming apparatus according to claim 3. The restricting portion moves in a direction symmetrical to the operation direction of the first regulating member and the first regulating member that regulates the position of one end in the width direction orthogonal to the paper transport direction, and the width of the paper. The image forming apparatus according to claim 4, further comprising a second regulating member that regulates the position of the other end in the direction. The image forming apparatus includes a rack that moves integrally with the first regulating member.
The detection means includes a gear for meshing with the rack to detect the paper width, and a rotary variable resistor in which a shaft portion is connected to the gear and the resistance value changes according to the rotation angle of the shaft portion. Have,
The image forming apparatus according to claim 5, wherein a voltage corresponding to the resistance value of the variable resistor, which is the detection signal, is output. The image forming apparatus according to claim 6, wherein the control means calculates the width of the paper loaded on the loading portion before the correction is performed by a linear expression using the voltage. The storage means stores the first correction data and the second correction data, and stores the first correction data and the second correction data.
The first correction data includes a value of the detection signal output from the detection means and the detection when the regulation unit is operated in a direction of narrowing the distance between the first regulation member and the second regulation member. It has the value of the signal and the associated difference,
The second correction data includes a value of the detection signal output from the detection means and the detection when the regulation unit is operated in a direction of widening the distance between the first regulation member and the second regulation member. The image forming apparatus according to claim 7, wherein the image forming apparatus has the difference associated with the value of the signal. When the control means calculates a difference according to the value of the detection signal output from the detection means, the direction in which the regulation unit is operated is the direction in which the first regulation member and the second regulation member are operated. The first correction data or the second correction data stored in the storage means, depending on whether the distance is narrowed or the distance between the first regulating member and the second regulating member is widened. The image forming apparatus according to claim 8, wherein the image forming apparatus is selected. The claim is characterized in that the difference corresponding to the value of the detection signal included in the first correction data is smaller than the difference corresponding to the detection signal having the same value as the detection signal possessed by the second correction data. 9. The image forming apparatus according to 9. The claim is characterized in that the difference corresponding to the value of the detection signal included in the second correction data is smaller than the difference corresponding to the detection signal having the same value as the detection signal possessed by the first correction data. 9. The image forming apparatus according to 9. The regulation when the regulation unit is operated in the direction of narrowing the distance between the first regulation member and the second regulation member and the regulation in the direction of widening the distance between the first regulation member and the second regulation member. The difference from the difference when the unit is operated is the gap between each component interposed for transmitting the amount of movement of the first regulating member from the first regulating member to the gear by the operation of the regulating unit. The image forming apparatus according to claim 10 or 11, wherein the image forming apparatus is generated by deformation of each of the parts due to a force applied to the first regulating member by the operation.