JP7814908B2 - Image forming system - Google Patents

Description

The present invention relates to an image forming system, and more particularly to a method for adjusting the positional deviation of a sheet relative to an image forming unit in an image forming apparatus, in an image forming system including a sheet feeding device and an image forming apparatus.

Conventionally, image forming devices such as printers and copiers have included optional sheet feeders that allow additional sheets to be loaded in addition to the sheet stack that can be accommodated within the device in order to reduce the number of times sheets need to be refilled. During image formation, sheets are sequentially fed from a stacking section toward an image forming section, where an image is formed on the sheet. Sheet feeders are typically stacked in multiple tiers. Sheets fed from a lower-tier sheet feeder are sequentially transported through an upper-tier sheet feeder before reaching the image forming device. Each sheet feeder and image forming device are often positioned using pins and holes, for example. Furthermore, sheet feeders have a paper feed cassette as a storage section for storing sheets. Paper feed cassettes typically have a guide member for positioning and holding sheets in a direction perpendicular to the sheet feed direction. The guide member has an operating side and a driven side, and many devices are configured so that when the operating side is moved, the driven side moves the same distance in the opposite direction to the operating side. The guide on the operating side moves in accordance with the scale that indicates the position for each size of sheet being loaded, so that the center of the loaded sheets is aligned with the reference position of the loading section.

In printer systems that combine multiple sheet feeding devices and image forming devices, in addition to the cumulative effect of tolerances between each component, misalignment can occur at the connections between sheet feeding devices and between sheet feeding devices and image forming devices. Misalignment at each connection can cause misalignment between the image forming unit and storage unit, resulting in images not being formed in the specified position on the sheet, leading to reduced print quality.

Some printers are capable of pre-adjusting the image writing position to match the sheet position, but there is a limit to the amount of adjustment. Furthermore, in laser beam printers, misalignment between the image forming device and the sheet can cause the fixing heater to heat up around the edges of the sheet in the width direction, resulting in reduced throughput. As printing speeds increase, the tolerance for misalignment between the sheet and the image forming unit is currently decreasing. To address this, some printers are designed to allow the relative position of the paper feed cassette and guide member to be adjusted (see, for example, Patent Document 1). In this configuration, a holding member is provided that is slidably attached in the width direction of the paper. The holding member holds the sheet guide member, rack, and pinion, allowing the sheet guide position to be adjusted.

Patent No. 6347222

However, in printer systems using multiple tiers of sheet feeders, the sheet feeder with casters is often the lowest tier, with multiple tiers of sheet feeders stacked on top of the image forming device. When installing or moving a printer, the entire multi-tiered printer system must be manually pushed and moved. This can result in unexpectedly large displacement of the sheet feeder due to vibrations during movement and the possibility of the sheet feeder accidentally hitting a wall or a step. Furthermore, because misalignment between each tier of sheet feeders accumulates, the positional misalignment between the sheet held in the lowest sheet feeder and the image forming device is likely to increase as the number of tiers of sheet feeders installed increases. With conventional guide member adjustment configurations, attempting to achieve a large adjustment amount increases the overall size of the device, making it difficult to achieve a large adjustment amount. Therefore, when stacking multiple tiers of sheet feeders, there is an issue where the adjustment amount is insufficient to offset the overall misalignment.

The present invention was developed in response to these circumstances, and aims to adjust misalignment in a printer system in which sheet feeding devices are stacked, without being affected by the number of stacking levels.

In order to solve the above-mentioned problems, the present invention has the following configuration.
(1) An image forming system comprising: a first device having a first top surface perpendicular to a vertical direction and a first bottom surface disposed below the first top surface in the vertical direction and parallel to the first top surface; and a second device having a second top surface perpendicular to the vertical direction and a second bottom surface disposed below the second top surface in the vertical direction and parallel to the second top surface, wherein the first device is stacked on the second device in the vertical direction, with the second top surface facing the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material, the image forming system further comprising a positioning unit that determines a position of the first device when stacked on the second device in a horizontal direction perpendicular to the vertical direction, and the positioning unit is configured to position the first device when stacked on the second device. an adjustment unit that adjusts a relative positional misalignment between the first device and the second device in a horizontal direction , wherein the first bottom surface has a through hole, and the second top surface has a first axis portion parallel to the vertical direction, the adjustment unit has a first member and a second member, the first member has a first hole portion that fits into the first axis portion and at least three surfaces that are parallel to the vertical direction and surround the first hole portion, and the second member has at least three inner surfaces that respectively contact the at least three surfaces and an outer periphery that surrounds the at least three inner surfaces and fits into the through hole, and the adjustment unit adjusts the positional misalignment by changing the state of contact between the at least three surfaces and the at least three inner surfaces .
(2) An image forming system including: a first device having a first top surface perpendicular to a vertical direction and a first bottom surface that is provided below the first top surface in the vertical direction and parallel to the first top surface; and a second device having a second top surface perpendicular to the vertical direction and a second bottom surface that is provided below the second top surface in the vertical direction and parallel to the second top surface, wherein the first device is stacked on the second device in the vertical direction, and the second top surface faces the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material, the image forming system including a positioning unit that determines the position of the first device when stacked on the second device in a horizontal direction perpendicular to the vertical direction, and the positioning unit is configured to position the first device when stacked on the second device. an adjustment unit that adjusts a relative positional misalignment between the first device and the second device in the horizontal direction, wherein the first bottom surface has a first axis portion parallel to the vertical direction, and the second top surface has a through hole; the adjustment unit has a first member and a second member, the first member having a first hole portion that fits into the first axis portion and at least three surfaces that are parallel to the vertical direction and surround the first hole portion; the second member having at least three inner surfaces that respectively contact the at least three surfaces, and an outer periphery that surrounds the at least three inner surfaces and fits into the through hole; and the adjustment unit adjusts the positional misalignment by changing the state of contact between the at least three surfaces and the at least three inner surfaces.
(3) An image forming system comprising: a first device having a first top surface perpendicular to a vertical direction and a first bottom surface that is disposed below the first top surface in the vertical direction and parallel to the first top surface; and a second device having a second top surface perpendicular to the vertical direction and a second bottom surface that is disposed below the second top surface in the vertical direction and parallel to the second top surface, wherein the first device is stacked on the second device in the vertical direction, and the second top surface faces the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material, the image forming system further comprising a positioning unit that determines a position of the first device when stacked on the second device in a horizontal direction perpendicular to the vertical direction, and the positioning unit is configured to determine a position of the first device when stacked on the second device in the horizontal direction. an adjustment unit that adjusts a relative positional deviation between the first device and the second device, wherein the first bottom surface has a through hole, and the second top surface has a first sliding shaft and a second sliding shaft; the adjustment unit has a second shaft portion that fits into the through hole, a rotating portion that rotates around the second shaft portion, a first sliding hole portion that is provided in the rotating portion and has a curved elliptical shape and fits onto the first sliding shaft, and a second sliding hole portion that is provided in the rotating portion and has a curved elliptical shape and fits onto the second sliding shaft; the second sliding shaft and the second sliding hole portion are arranged in a position that is line-symmetrical with the first sliding shaft and the first sliding hole portion with respect to the second shaft portion, and have the line-symmetrical shape; and the adjustment unit adjusts the positional deviation by rotating the rotating portion.

This invention makes it possible to adjust misalignment in a printer system in which sheet feeding devices are stacked, without being affected by the number of stacking levels.

FIG. 1 is a schematic cross-sectional front view showing the overall configuration of an image forming system according to first to third embodiments. FIG. 10 is a diagram illustrating a positioning method of the sheet feeding device according to the first to third embodiments. FIG. 1 is a diagram illustrating an outline of a paper feed cassette according to first to third embodiments. FIG. 1 is a diagram illustrating the configuration of a relative position adjustment mechanism according to the first embodiment. 1 is a cross-sectional view of an axial portion of an inner member and an outer member according to a first embodiment of the present invention; FIG. 10 is a diagram illustrating the operation of the relative position adjustment mechanism according to the first embodiment. FIG. 1 is a diagram illustrating the difference between the effects of the first embodiment and the effects of the conventional example. FIG. 10 is a diagram illustrating the configuration of a relative position adjustment mechanism according to a second embodiment. FIG. 10 is a diagram illustrating the operation of the relative position adjustment mechanism according to the second embodiment. FIG. 10 is a diagram illustrating the configuration of a relative position adjustment mechanism according to a third embodiment. FIG. 10 is a diagram illustrating the operation of the relative position adjustment mechanism according to the first embodiment.

The following describes in detail the embodiments of the present invention, by way of example, with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in these embodiments should be modified as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, it is not intended that the scope of the present invention be limited to the following embodiments.

[Image forming system]
The first embodiment will be described in detail below with reference to the accompanying drawings. FIG. 1 is a front cross-sectional view showing a schematic configuration of a printer system 100, which is an example of an image forming system according to the first embodiment, in which a laser beam printer and a sheet feeding device are stacked. The printer system 100 in FIG. 1 shows a configuration in which, for example, an image forming apparatus is mounted on top of two stacked sheet feeding devices. Note that one or more sheet feeding devices may be disposed below the image forming apparatus. The image forming apparatus and the two sheet feeding devices operate in cooperation to form images on sheets, which are recording materials. When focusing on the image forming apparatus and the sheet feeding device below the image forming apparatus, the image forming apparatus corresponds to a first device, and the sheet feeding device corresponds to a second device. When focusing on the sheet feeding device and the sheet feeding device below it, the upper sheet feeding device corresponds to the first device, and the lower sheet feeding device corresponds to the second device.

The first device has a first top surface perpendicular to the vertical direction, and a first bottom surface located below the first top surface in the vertical direction and parallel to the first top surface. The second device has a second top surface perpendicular to the vertical direction, and a second bottom surface located below the second top surface in the vertical direction and parallel to the second top surface. Printer system 100 is an example of an image forming system in which the first device is stacked above the second device in the vertical direction, with the second top surface facing the first bottom surface, and the first and second devices operate in cooperation to form an image on a recording material.

The printer system 100 includes a laser beam printer 1 (hereinafter referred to as printer 1), which is an image forming apparatus. A paper feed cassette 11, which holds a stack of sheets Sa and is set in the printer 1, is located below the printer 1. The paper feed unit 31 includes a pickup roller 32 that feeds out the topmost sheet S1 of the sheet stack Sa stacked in the paper feed cassette 11, which serves as a storage unit, and a separation roller pair 33 that separates the sheets S fed by the pickup roller 32. Here, the separation roller pair 33 is composed of a feed roller 34 and a retard roller 35. The printer 1 also includes a transport roller 36 that transports sheets S separated and fed one by one from the sheet stack Sa by the separation roller pair 33 toward the image forming unit 21.

The printer system 100 includes a sheet feeding device 2a located on the upper level. The sheet feeding device 2a is stacked on top of the sheet feeding device 2b, with the printer 1 stacked on top. Similar to the printer 1, the sheet feeding device 2a houses a paper feed cassette 11a containing a stack of sheets Sa. The paper feed cassette 11a has a pickup roller 45a and a separation roller pair 46a, and the uppermost sheet S1a is fed out by the pickup roller 45a and separation roller pair 46a. The sheet S1a sent towards the printer 1 by the transport roller 47a passes through a transport path 50, merges with the transport path inside the printer 1, and is sent to the image forming unit 21. The transport path 50 of the printer 1 is a transport path for transporting the sheet S transported from the sheet feeding device 2a.

The printer system 100 includes a sheet feeding device 2b located at the bottom. The sheet feeding device 2b is located at the bottom of the printer system 100, with the sheet feeding device 2a and printer 1 stacked above. The sheet feeding device 2b has the same structure as the sheet feeding device 2a, and components with the same functions are identified by the same numerals followed by the letter "b" to distinguish them. The topmost sheet S1b, fed from cassette 11b of sheet feeding device 2b by pickup roller 45b and separation roller pair 46b, is transported to the transport path 51a provided within sheet feeding device 2a by transport roller 47b within sheet feeding device 2b. Sheet S1b passes through the transport path 51a and is handed over to transport roller 47a within sheet feeding device 2a. Sheet S1b is then transported to the image forming unit 21 via the same path as when it was fed from sheet feeding device 2a. FIG. 1 shows an example in which two sheet feeders are stacked, but the sheet S transport operation is the same even when an additional sheet feeder is stacked.

The transport path 51a is a transport path for transporting (transferring) the sheet S from the lower sheet feeding device 2b into the sheet feeding device 2a. The sheet feeding device 2b also has a transport path 51b. The transport path 51b is provided for transporting the sheet S from the lower sheet feeding device into the sheet feeding device 2b when another sheet feeding device is placed below the sheet feeding device 2b.

The image forming unit 21 is a unit that forms images using an electrophotographic method. It includes a photosensitive drum 22 that forms a toner image and a transfer roller 23 that transfers the toner image formed on the photosensitive drum 22 to a sheet S fed from the paper feed cassette 11. The printer 1 includes a fixing unit 24 downstream of the image forming unit 21 in the conveyance direction of the sheet S. The fixing unit 24 applies heat and pressure to the sheet S to which the unfixed toner image has been transferred, fixing the toner image to the sheet S, thereby forming an image on the sheet S. The sheet S with the image formed is discharged by a discharge roller 25 to a discharge unit 26 located at the top of the printer 1. In the following description, when there is no need to distinguish between the sheet feeding device 2a and the sheet feeding device 2b, they will be referred to as the sheet feeding device 2. The positioning unit 40, positioning pins 41 (41a, 41b), positioning holes 43 (43a, 43b), etc. will be described later. The Y direction is the direction in which the sheet is fed (hereinafter referred to as the feeding direction).

[Sheet Feeding Device]
FIG. 2 is a schematic diagram of the entire sheet feeding device 2. FIG. 2 shows the entire sheet feeding device 2b in the lower row in FIG. 1 and a schematic diagram of the bottom surface 252a, which is the first bottom surface of the upper sheet feeding device 2a. When it is not necessary to distinguish between the individual sheet feeding devices 2, the letters a, b, etc. are omitted. The sheet feeding device 2 has a top surface 250, which is the first or second top surface, a bottom surface 252, which is the first or second bottom surface, positioning pins 41, 42, and positioning holes 43, 44, which are through-holes in the first bottom surface. FIG. 2 only shows the bottom surface 252a of the sheet feeding device 2a, which has positioning holes 43a, 44a. Two positioning holes (not shown) are also provided in the X direction on the bottom surface (not shown) of the printer 1, at positions corresponding to the positioning pins (not shown) of the sheet feeding device 2a. Here, the positioning hole 43 and the positioning pin 41 are referred to as the positioning portion 40A, and the positioning hole 44 and the positioning pin 42 are referred to as the positioning portion 40B. In Fig. 2, the positioning hole 43a and the positioning pin 41b are the positioning portion 40A, and the positioning hole 44a and the positioning pin 42b are the positioning portion 40B. Note that when there is no particular need to distinguish between the positioning portion 40A and the positioning portion 40B, the letters A and B may be omitted.

Here, the direction in which the positioning pins 41 and 42 (or the positioning holes 43 and 44) are aligned is the X direction, and the positioning pin 41 side is the negative side of the X direction. The negative side of the X direction is sometimes referred to as the right and the positive side as the left. Furthermore, the direction parallel to the top surface 250 and the bottom surface 252 and perpendicular to the X direction is the Y direction, and the side where the positioning pins 41, 42 and the positioning holes 43, 44 are located is the positive side of the Y direction. Note that when the sheet feeding device 2 is installed below the printer 1, it is installed so that the Y direction is the feeding direction of the sheet S and the positive side of the Y direction is the traveling (feeding) direction of the sheet S. In other words, the X direction is the direction perpendicular to the feeding direction of the sheet S and is the width direction of the sheet S. In an image forming system, misalignment in the X direction between devices can degrade the quality of the image formed on the sheet. Therefore, in Example 1, for example, misalignment in the X direction is adjusted.

The positioning unit 40 has positioning pins 41 and 42 provided on the top surface 250 of the sheet feeding device 2 and positioning holes 43 and 44 provided on the bottom surface 252 of the sheet feeding device 2 or the printer 1. The position of the sheet feeding device 2 is determined by fitting the positioning pin 41 into the positioning hole 43 and the positioning pin 42 into the positioning hole 44, respectively. The positioning unit 40 determines the position of the first device when it is stacked on the second device in the horizontal direction perpendicular to the up-down direction. The relative position adjustment mechanism 200 of Example 1 is mounted on the positioning pins 41 and 42. Details of the relative position adjustment mechanism 200 will be described separately.

The sheet feeding device 2 has two positioning units 40 (40A, 40B), one at the positive end and one at the negative end of the top surface 250 in the X direction. The positioning hole 44 is a hole that serves as a reference in the X and Y directions and is, for example, a circular hole. When the positioning pin 42 fits into the positioning hole 44, movement in the X and Y directions at this position is restricted. The positioning hole 43 is an elongated hole with a length W in the Y direction shown in Figure 2 that fits with the positioning pin 41, and its longitudinal direction is the X direction. The positioning hole 43 serves to prevent the device (sheet feeding device 2 or printer 1) loaded above it from rotating around the positioning pin 42. Because the positioning hole 43 is an elongated hole (elliptical) with its longitudinal direction in the X direction, movement of the positioning pin 41 in the Y direction is restricted, but movement in the X direction is possible within the range of the X-direction length of the positioning hole 43.

[Paper Cassette]
FIG. 3 is a schematic diagram showing the configuration of the sheet feed cassette 11. The sheet feed cassette 11 has a rear end guide unit 14, a pair of side guides 12, and a lifter unit 13. The rear end guide unit 14 is a guide unit that regulates the position of the sheets S in a feeding direction 141 of the sheets S. The pair of side guides 12 is a guide pair that regulates the position of the sheets S in a direction 142 perpendicular to the feeding direction 141. The lifter unit 13 is configured to stack and lift the sheet stack Sa. The lifter unit 13 is composed of a middle plate 120 and a lift arm 121. The lift arm 121 rotates by receiving driving force from a drive motor (not shown). The middle plate 120 is disposed above the lift arm 121 and is pushed by the lift arm 121 to rotate about a rotation shaft 120a, thereby lifting the sheet stack Sa stacked on the middle plate 120. As a result, the sheet stack Sa is supported from below by the intermediate plate 120 so as to be inclined upward with the side supported by the trailing end guide portion 14 as a fulcrum.

The side guide pair 12 includes a reference side guide 101, a pressing side side guide 102, a rotating shaft 109, a pinion 110, a rack pair 111, and an operating lever 103. The side guides 101 and 102 fit into guide grooves (not shown) provided in the paper feed cassette 11 and are held so as to be movable in the width direction of the sheet S. The width direction of the sheet S is a direction 142 perpendicular to the feeding direction 141. The rack pair 111 is positioned to sandwich the pinion 110. Therefore, when the pressing side guide 102 moves, the reference side guide 101 moves the same distance in the opposite direction via the pinion 110, thereby serving to hold the sheet S approximately in the center of the paper feed cassette 11.

The user moves the side guide 102 to a position appropriate for the size of the sheet stack Sa, then loads the sheet stack Sa into the paper feed cassette 11 and sets the paper feed cassette 11 in the printer 1. Next, the middle plate 120 lifts up to a position where the pickup roller 32 can feed the top sheet S1, completing preparations for paper feeding.

[Relative position adjustment mechanism]
The relative position adjustment mechanism 200 of the first embodiment will be described. The positioning unit 40 of the first embodiment has a relative position adjustment mechanism, which is an adjustment unit that adjusts the relative positional deviation between the first device and the second device in the horizontal direction. FIG. 4 is an exploded perspective view showing the relative position adjustment mechanism 200. The relative position adjustment mechanism 200 has an inner member 210 and an outer member 220. A reference pin 201, which is a first shaft portion parallel to the vertical direction, is fixed to a top surface 250, which is a second top surface of the sheet feeding device 2. Screw holes 202a and 202b and a rotation stop boss 203 are provided around the reference pin 201.

The inner member 210, which is the first member, has a through-hole 212 in its center, which is the first hole portion that fits over the reference pin 201. The inner member 210 also has a rotation prevention hole 213 and screw fixing holes 214a and 214b. The shaft portion 211 of the inner member 210 is, for example, in the shape of a rectangular prism, and has four side surfaces, which will be described later. In other words, the inner member 210 has four surfaces that are parallel in the vertical direction and surround the first hole portion. The outer periphery of the shaft portion 211 of the inner member 210 has a cross section that is rectangular in a virtual plane formed by the X and Y directions (hereinafter referred to as the XY plane).

The second member, the outer member 220, has a shaft portion 221, and the inner surface 222 of the shaft portion 221 has a shape described below that contacts and fits with the four surfaces of the shaft portion 211 of the inner member 210. That is, the outer member 220 has four inner surfaces that contact the four surfaces of the inner member 210. The outer member 220 has a boss hole 223 and screw fixing holes 224a and 224b. The outer periphery 221a of the outer member 220 is, for example, cylindrical in shape so that it can fit into positioning holes 43 and 44 provided in the printer 1 or sheet feeding device 2 to determine its position.

The reference pin 201 fits into the through hole 212 of the inner member 210, and the rotation stopper 203 fits into the rotation stopper hole 213, setting the inner member 210 in the sheet feeding device 2. The outer member 220 is then placed over the inner member 210. The inner periphery 222 of the outer member 220 contacts the shaft portion 211 of the inner member 210 on four surfaces, thereby restricting rotation of the outer member 220 around the shaft portion 221 relative to the inner member 210. Screws (not shown) are passed through the screw fixing holes 214a, 214b of the inner member 210 and the screw fixing holes 224a, 224b of the outer member 220, and are fastened into the screw holes 202a, 202b provided on the top surface 250 of the sheet feeding device 2. As a result, the relative position adjustment mechanism 200 is fixed to the sheet feeding device 2, and the printer 1 or another sheet feeding device 2 is placed on top, making it possible to define the relative position. For example, in the case of the printer system 100 of FIG. 1, it becomes possible to define the relative position of the sheet feeding device 2a with respect to the printer 1, or the relative position of the sheet feeding device 2b with respect to the sheet feeding device 2a.

[Configuration of the shaft portion of the inner member]
Next, an adjustment method of the relative position adjustment mechanism 200 will be described with reference to FIG. 5 . FIG. 5 is a view seen from the bottom of FIG. 4 . FIG. 5(A) shows a cross section of the shaft portion 221 of the inner member 210 in the XY plane. The shaft portion 211 of the inner member 210 has four surfaces, specifically, a first surface 215, a second surface 216, a third surface 217, and a fourth surface 218. The first surface 215 has a first protruding surface 215a and a first retracted surface 215b. The third surface 217 has a second protruding surface 217a and a second retracted surface 217b. The shaft portion 211 has a first notch portion 219a, a second notch portion 219b, a third notch portion 219c, and a fourth notch portion 219d. In detail, first cutout portion 219a is a portion that connects fourth surface 218 and first surface 215, and second cutout portion 219b is a portion that connects first surface 215 and second surface 216. Third cutout portion 219c is a portion that connects second surface 218 and third surface 217, and fourth cutout portion 219d is a portion that connects third surface 217 and fourth surface 218.

The second surface 216, the fourth surface 218, the first protruding surface 215a, and the second recessed surface 217b are all approximately the same distance from the center O1 of the through hole 212. That is, the first distance d1 (hereinafter referred to as distance d1), the second distance d2 (hereinafter referred to as distance d2), the third distance d3 (hereinafter referred to as distance d3), and the fourth distance d4 (hereinafter referred to as distance d4) are all approximately the same (d1 = d2 = d3 = d4). Note that "approximately the same" here includes distances that are strictly the same and distances that are determined to be substantially the same. Distance d1 is the distance from the center O1 of the through hole 212 to the first protruding surface 215a. Distance d2 is the distance from the center O1 of the through hole 212 to the second surface 216. Distance d3 is the distance from the center O1 of the through hole 212 to the second recessed surface 217b. Distance d4 is the distance from the center O1 of the through hole 212 to the fourth surface 218.

On the other hand, the first recessed surface 215b is configured so that the fifth distance d5 (hereinafter referred to as distance d5) from the center O1 of the through hole 212 is smaller than the distance d1 (d5 < d1). For example, the distance d5 is 0.5 mm smaller than the distance d1. The second protruding surface 217a is configured so that the sixth distance d6 (hereinafter referred to as distance d6) from the center O1 of the through hole 212 is greater than the distance d3 (d6 > d3). For example, the distance d6 is 0.5 mm larger than the distance d3. As a result, the sum of the distances d1 and d3 is equal to the sum of the distances d5 and d6 (d1 + d3 = d5 + d6).

[Configuration of shaft portion of outer member]
5(B) shows a cross section of the shaft portion 221 of the outer member 220 in the XY plane. The inner surfaces of the shaft portion 221 of the outer member 220 have four inner surfaces that face the four surfaces of the shaft portion 211 of the inner member 210. Specifically, the shaft portion 211 has a first inner surface 225, a second inner surface 226, a third inner surface 227, and a fourth inner surface 228. The first inner surface 225 has a first recess 225a. The second inner surface 226 has a second recess 226a. The third inner surface 227 has a third recess 227a. The fourth inner surface 228 has a fourth recess 228a.

The shaft portion 221 has a first corner 229a, a second corner 229b, a third corner 229c, and a fourth corner 229d on its inner surface. Specifically, the first corner 219a connects the fourth inner surface 228 to the first inner surface 225, and the second corner 219b connects the first inner surface 225 to the second inner surface 226. The third corner 219c connects the second inner surface 226 to the third inner surface 227, and the fourth corner 219d connects the third inner surface 227 to the fourth inner surface 228. The first corner 229a and the third corner 229c are farther from the center O2 of the circle defined by the outer periphery 221a of the shaft portion 221 (hereinafter referred to as the center of the outer periphery 221a) than the second corner 229b and the fourth corner 229d, resulting in a concave shape.

The seventh distance d12 (hereinafter referred to as distance d12) from the center O2 of the outer periphery 221a of the shaft portion 221 to the second inner surface 226 is the same as the eighth distance (hereinafter referred to as distance d14) from the center O2 to the fourth inner surface 228 (d12 = d14). Furthermore, the ninth distance d11 (hereinafter referred to as distance d11) from the center O2 to the first inner surface 225 is smaller than the distance d12 (distance d14) (d11 < d12 = d14), e.g., 0.5 mm smaller. The tenth distance (hereinafter referred to as distance d13) from the center O2 to the third inner surface 227 is larger than the distance d12 (distance d14) (d13 > d12 = d14), e.g., 1 mm larger.

[Adjustment of relative position adjustment mechanism]
Figure 6 is a cross-sectional view of the shaft portion 211 and the shaft portion 221 in the XY plane when the outer member 220 is attached to the inner member 210. Note that, to make the drawing easier to see in Figure 6, reference numerals are only assigned to Figure 6(C), and some are omitted in Figure 6(C) as well. The relative position adjustment mechanism 200 of Example 1 is configured to be adjustable to five positions. Figures 6(A) to 6(E) show the states adjusted to each position.

Figure 6 (C) shows the standard state, in which the center O2 of the shaft portion 221 of the outer member 220 and the center of the reference pin 201, in other words the center O1 of the shaft portion 211 of the inner member 210, are aligned. Note that the position of the imaginary line passing through the center O1 (center O2) in the standard state is designated x0. Also, the position of one imaginary line that is parallel to the imaginary line at position x0 and touches the outer periphery 221a of the shaft portion 221 of the outer member 220 in the standard state is designated x1. The position of the other imaginary line that is touches the outer periphery 221a of the shaft portion 221 on the opposite side of position x1 from the imaginary line at position x0 is designated x2.

(standard condition)
6(C), the first retracted surface 215b of the inner member 210 contacts the first inner surface 225 of the outer member 220, and the first protruding surface 215a of the inner member 210 protrudes toward the first recessed portion 225a of the outer member 220. The second surface 216 of the inner member 210 contacts the second inner surface 226 of the outer member 220. The second retracted surface 217b of the inner member 210 does not contact the third inner surface 227 of the outer member 220, and the second protruding surface 217a of the inner member 210 contacts the third inner surface 227 of the outer member 220. The fourth surface 218 of the inner member 210 contacts the fourth inner surface 228 of the outer member 220.

The first corner 229a of the outer member 220 faces the first cutout 219a of the inner member 210. The second corner 229b of the outer member 220 faces the second cutout 219a of the inner member 210. The third corner 229c of the outer member 220 faces the third cutout 219c of the inner member 210. The fourth corner 229d of the outer member 220 faces the fourth cutout 219d of the inner member 210. The relative position adjustment mechanism 200 adjusts the inner member 210 and the outer member 220 to a standard state in which the first surface and the first inner surface contact, the second surface and the second inner surface contact, the third surface and the third inner surface contact, and the fourth surface and the fourth inner surface contact. This position corresponds to the first adjustment position.

(The outer member is rotated 90 degrees clockwise from the standard position: rightward adjustment)
6(B) shows the state after the fixing screws have been removed from the standard state shown in Fig. 6(C), the outer member 220 has been rotated 90° clockwise, and is then fitted back into the inner member 210. The surface that contacts the second surface 216 of the inner member 210 changes from the second inner surface 226 to the third inner surface 227 of the outer member 220, and the surface that contacts the fourth surface 218 changes from the fourth inner surface 228 to the first inner surface 225.

In the state shown in FIG. 6(B), the first retracted surface 215b of the inner member 210 does not contact the second inner surface 226 of the outer member 220, and the first protruding surface 215a of the inner member 210 contacts the second inner surface 226 of the outer member 220. The second surface 216 of the inner member 210 contacts the third inner surface 227 of the outer member 220. The second retracted surface 217b of the inner member 210 contacts the fourth inner surface 228 of the outer member 220, and the second protruding surface 217a of the inner member 210 protrudes toward the fourth recessed portion 228a of the outer member 220. The fourth surface 218 of the inner member 210 contacts the first inner surface 225 of the outer member 220.

The first cutout 219a of the inner member 210 faces the second corner 229b of the outer member 220. The second cutout 219b of the inner member 210 faces the third corner 229c of the outer member 220. The third cutout 219c of the inner member 210 faces the fourth corner 229d of the outer member 220. The fourth cutout 219d of the inner member 210 faces the first corner 229a of the outer member 220.

The first inner surface 225 and the third inner surface 227 are each shifted 0.5 mm toward the third inner surface 227 (toward position x1) relative to the center O2 of the outer periphery 221a of the shaft portion 221 of the outer member 220. In other words, the midpoint of the sum of distances d11 and d13 is shifted toward the third inner surface 227 (inner surface) from center O2, by 0.5 mm. Therefore, the outer member 220 moves 0.5 mm to the right in FIG. 6 relative to the standard state. The position where the relative position adjustment mechanism 200 moves 0.5 mm to the right is the second adjustment position. At this time, the first protruding surface 215a and the third retracting surface 217b are in contact with the second inner surface 226 and the fourth inner surface 228, respectively. Because the distances from the center of these surfaces are all the same, the vertical position of the shaft portion 221 of the outer member 220 remains unchanged in FIG. 6.

(The outer member is rotated 90 degrees clockwise and the inner member is rotated 90 degrees counterclockwise from the standard position: rightward adjustment)
Figure 6(A) shows a state in which only the inner member 210 has been rotated 90° counterclockwise from the state shown in Figure 6(B). As in Figure 6(B), the outer member 220 has been rotated 90° clockwise from the standard state. The contact surfaces of the first inner surface 225 and the third inner surface 227 change to the second protruding surface 217a and the first retracted surface 215a, respectively.

In the state shown in FIG. 6(A), the first retracted surface 215b of the inner member 210 contacts the third inner surface 227 of the outer member 220, and the first protruding surface 215a of the inner member 210 protrudes toward the third recessed portion 227a of the outer member 220. The second surface 216 of the inner member 210 contacts the fourth inner surface 228 of the outer member 220. The second retracted surface 217b of the inner member 210 does not contact the first inner surface 225 of the outer member 220, and the second protruding surface 217a of the inner member 210 contacts the first inner surface 225 of the outer member 220. The fourth surface 218 of the inner member 210 contacts the second inner surface 226 of the outer member 220.

The first corner 229a of the outer member 220 faces the third notch 219c of the inner member 210. The second corner 229b of the outer member 220 faces the fourth notch 219d of the inner member 210. The third corner 229c of the outer member 220 faces the first notch 219a of the inner member 210. The fourth corner 229d of the outer member 220 faces the second notch 219b of the inner member 210.

The first recessed surface 215b is 0.5 mm closer to the center of the reference pin 201 than the first protruding surface 215a, and the second protruding surface 217a is 0.5 mm farther from the center of the reference pin 201 than the second recessed surface 217b. Therefore, the outer member 220 in FIG. 6(A) shifts an additional 0.5 mm to the right from the state in FIG. 6(B). In other words, combined with the 0.5 mm shift of the first inner surface 225 and the third inner surface 227, the outer member 220 moves 1.0 mm to the right relative to FIG. 6(C). The position where the relative position adjustment mechanism 200 moves 1.0 mm to the right is the third adjustment position. At this time, the fourth surface 218 and the second surface 216 are in contact with the second inner surface 226 and the fourth inner surface 228, respectively, and the distances d2 and d4 from the centers of these surfaces are all the same (d2 = d4). Therefore, the position of the shaft 221 of the outer member 220 in the vertical direction in Figure 6 remains unchanged. This is the adjustment method when adjusting the relative position adjustment mechanism 200 to the right from the standard state in Figure 6 (C).

(The outer member is rotated 90 degrees counterclockwise from the standard position: leftward adjustment)
On the other hand, adjustment to the left can be achieved by rotating the outer member 220 in the opposite direction (counterclockwise) to the adjustment shown in FIGS. 6A and 6B. FIG. 6D shows the state in which the outer member 220 has been rotated 90° counterclockwise, adjusting it 0.5 mm to the left. The position in which the relative position adjustment mechanism 200 has moved 0.5 mm to the left is the fourth adjustment position. In the state shown in FIG. 6D, the first retracted surface 215b of the inner member 210 does not contact the fourth inner surface 228 of the outer member 220, and the first protruding surface 215a of the inner member 210 contacts the fourth inner surface 228 of the outer member 220. The second surface 216 of the inner member 210 contacts the first inner surface 225 of the outer member 220. The second retracted surface 217b of the inner member 210 contacts the second inner surface 226 of the outer member 220, and the second protruding surface 217a of the inner member 210 protrudes toward the second recessed portion 226a of the outer member 220. The fourth surface 218 of the inner member 210 contacts the third inner surface 227 of the outer member 220.

The third cutout 219c of the inner member 210 faces the second corner 229b of the outer member 220. The fourth cutout 219d of the inner member 210 faces the third corner 229c of the outer member 220. The first cutout 219a of the inner member 210 faces the fourth corner 229d of the outer member 220. The second cutout 219b of the inner member 210 faces the first corner 229a of the outer member 220. Figure 6(D) shows a state rotated 180 degrees from Figure 6(B).

(The outer member is rotated 90 degrees counterclockwise and the inner member is rotated 90 degrees clockwise from the standard position: leftward adjustment)
Figure 6(E) shows the state in which the inner member 210 has been rotated 90° clockwise from the state in Figure 6(D) and adjusted 1.0 mm to the left. The position where the relative position adjustment mechanism 200 has moved 1.0 mm to the left is the fifth adjustment position. In the state in Figure 6(E), the first retracted surface 215b of the inner member 210 contacts the third inner surface 227 of the outer member 220, and the first protruding surface 215a of the inner member 210 protrudes toward the third recessed portion 227a of the outer member 220. The second surface 216 of the inner member 210 contacts the fourth inner surface 228 of the outer member 220. The second retracted surface 217b of the inner member 210 does not contact the first inner surface 225 of the outer member 220, and the second protruding surface 217a of the inner member 210 contacts the first inner surface 225 of the outer member 220. The fourth surface 218 of the inner member 210 contacts the second inner surface 226 of the outer member 220 .

The first corner 229a of the outer member 220 faces the third notch 219c of the inner member 210. The second corner 229b of the outer member 220 faces the fourth notch 219d of the inner member 210. The third corner 229c of the outer member 220 faces the first notch 219a of the inner member 210. The fourth corner 229d of the outer member 220 faces the second notch 219b of the inner member 210. Figure 6(E) shows a state rotated 180 degrees from Figure 6(A).

Constructing the relative position adjustment mechanism 200 as in Example 1 allows adjustment in only one axial direction (a specific direction) that requires adjustment. The positioning pins 41 and 42 in Figure 2 are adjusted, for example, as shown in Figure 6(D). In other words, when the outer member 220 of the relative position adjustment mechanism 200 is rotated 90 degrees counterclockwise from the standard state in Figure 2, the outer circumferences of the positioning pins 41 and 42 shift 0.5 mm in the +X direction. This also shifts the positioning holes 43a and 44a, which are fitted with the positioning pins 41b and 42b, respectively, by 0.5 mm in the +X direction. Therefore, the entire assembly, including the upper sheet feeding device 2a and the printer 1 mounted thereon, moves 0.5 mm in the +X direction, achieving position adjustment. In Example 1, the adjustment amounts are set to ±0.5 mm and ±1.0 mm, but are not limited to these. In Example 1, the required shift amount can be set arbitrarily by setting the distances d1 to d6 of the inner member 210 and the distances d11 to d14 of the outer member 220 to a predetermined relationship.

As described above, each surface of the outer periphery of the inner member has multiple surfaces at different distances from the reference axis, changing the angle at which the inner and outer members fit together. In other words, the relative position adjustment mechanism 200, which serves as the adjustment unit, adjusts the positional misalignment by changing the state of contact between the four surfaces of the inner member 210 and the four inner surfaces of the outer member 220. This changes the combination of surfaces that contact the inner periphery surface of the outer member and the outer periphery surface of the inner member. In this way, the position of the center of the outer periphery of the outer member relative to the center of the reference axis is adjusted.

[effect]
Next, we will explain the difference between adjustment using the sheet feeding device 2 incorporating the relative position adjustment mechanism 200 of the first embodiment and adjustment using a conventional technique for adjusting the position of the guide member 12 of the paper feed cassette 11, and then explain the effects of the first embodiment. FIG. 7 is a conceptual diagram of an image forming system 350 in which a printer 1 is mounted on four stacked sheet feeding devices 2a, 2b, 2c, and 2d. The center of the image forming unit housed inside the printer 1 is represented by center line 300. The center of sheet feeding device 2a is represented by center line 301a, the center of sheet feeding device 2b is represented by center line 301b, the center of sheet feeding device 2c is represented by center line 301c, and the center of sheet feeding device 2d is represented by center line 301d. All of these are indicated by dashed dotted lines. Furthermore, the offset between the center lines of the printer 1 and the sheet feeding device 2a is represented by offset 312a, and the offset between the center lines of the sheet feeding devices 2a and 2b is represented by offset 312b. Further, the deviation between the center lines of the sheet feeding apparatus 2b and the sheet feeding apparatus 2c is a deviation 312c, and the deviation between the center lines of the sheet feeding apparatus 2c and the sheet feeding apparatus 2d is a deviation 312d.

Let's look at the misalignment between the top printer 1 and the bottom sheet feeding device 2d in the image forming system 350. In the case of conventional technology, the amount of shift required to correct this misalignment using the guide member 12 in the paper feed cassette 11 is 312a + 312b + 312c + 312d. In other words, the misalignment accumulates for each stage, and it becomes increasingly disadvantageous the lower you go.

On the other hand, when the relative position adjustment mechanism 200 of Example 1 is applied, first, the misalignment in the range of the upper part 320 of sheet feeding device 2a is adjusted by adjusting sheet feeding device 2a. Next, the misalignment in the range of the upper part 321 of sheet feeding device 2b is adjusted by adjusting sheet feeding device 2b. Similarly, the misalignment in the range of the upper part 322 of sheet feeding device 2c is adjusted by adjusting sheet feeding device 2c, and the misalignment in the range of the upper part 323 of sheet feeding device 2d is adjusted by adjusting sheet feeding device 2d. This means that the adjustment has an effect on all sheets stacked above the adjusted sheet feeding device 2, and the misalignment of each layer is corrected by adjusting each layer and does not accumulate in devices below each layer. In other words, the required shift amount for sheet feeding device 2d is also the dimension of misalignment 312d. Thus, according to Example 1, even when multiple sheet feeding devices are stacked, misalignment does not accumulate, and the adjustment required for misalignment can be reduced, making it possible to achieve good print quality with a space-saving relative position adjustment mechanism.

Furthermore, although the shaft portion of the inner member has been described as having four faces, this is not limiting. The outer peripheral shape of the inner member is not limited to a shape having four faces, and may be, for example, a polygon having three or more faces. In this case, the inner peripheral shape of the outer member only needs to have the same number of faces as the outer peripheral shape of the inner member, and all of the outer peripheral faces of the inner member must face all of the inner peripheral faces of the outer member when the outer member is fitted to the inner member.
Furthermore, the first bottom surface may have a first axis portion parallel to the vertical direction, and the second top surface may have a through-hole. That is, in the opposite configuration to that shown in FIG. 2 , the positioning pins 41 and 42 (relative position adjustment mechanism 200) may be provided on the bottom surface 252, and the positioning holes 43 and 44 may be provided on the top surface 250.

As described above, according to Example 1, misalignment in a printer system in which sheet feeding devices are stacked can be adjusted without being affected by the number of stacking levels.

[Relative position adjustment mechanism]
A second embodiment will now be described. Descriptions of parts that are the same as those in the first embodiment will be omitted. FIG. 8 shows a relative position adjustment mechanism 400, which is an adjustment unit in the second embodiment. FIG. 8A is a top view of the relative position adjustment mechanism 400, and FIG. 8B is a perspective view. As shown in FIG. 8 , in the second embodiment, a first sliding shaft 401a (hereinafter referred to as the sliding shaft 401a) and a second sliding shaft 401b (hereinafter referred to as the sliding shaft 401b) are provided on the top surface 250, which is the second top surface of the sheet feeding device 2. The relative position adjustment mechanism 400 has a rotating plate 422, which is a rotating unit, and an adjustment shaft 423, which is a second shaft unit fixed to the rotating plate 422. The rotating plate 422 and the adjustment shaft 423 constitute a rotation adjustment unit 420.

The rotating plate 422 is provided with a first sliding hole 421a and a second sliding hole 421b that mate with the sliding shafts 401a and 401b and regulate the movement of the rotation adjustment unit 420. The sliding hole 421a mates with the sliding shaft 401a, and the sliding hole 421b mates with the sliding shaft 401b. The sliding hole 421a has a curved elliptical shape, with the center line Ca of the sliding hole 421a being farther from the adjustment shaft 423 at one end and closer to the adjustment shaft 423 at the other end. The sliding hole 421a is not limited to a curved elliptical shape, as long as the center line Ca approaches the adjustment shaft 423 from one end to the other. The rotating plate 422 is also provided with screw holes 424a and 424b.

Sliding hole 421b also has a curved elliptical shape, with the center line Cb of sliding hole 421b being farther away from adjustment shaft 423 at one end and closer to adjustment shaft 423 at the other end. Here, the direction passing through center O3 of adjustment shaft 423 and in which adjustment shaft 423 is adjusted is defined as direction 430. Furthermore, a virtual line passing through center O3 of adjustment shaft 423 and perpendicular to direction 430 is defined as line L1. Sliding hole 421b is positioned symmetrically to sliding hole 421a with respect to line L1, and its shape is also symmetrical to sliding hole 421a with respect to line L1.

When the rotating plate 422 rotates clockwise around the adjustment shaft 423 in direction 430, the sliding holes 421a and 421b have the following shape. That is, the sliding shaft 401a sliding along the sliding hole 421a moves away from the adjustment shaft 423, while the sliding shaft 401b sliding along the sliding hole 421b moves closer to the adjustment shaft 423. The amount by which the sliding hole 421a moves away from the adjustment shaft 423 is the same as the amount by which the sliding hole 421b moves closer to the adjustment shaft 423. By sliding the sliding shaft 401a along the sliding hole 421a and the sliding shaft 401b along the sliding hole 421b, the adjustment shaft 423 moves along direction 430. For this reason, direction 430 is also referred to as the adjustment direction 430, and the direction of movement is expressed as the right or left side of the adjustment direction 430.

[Adjustment method]
(standard state, moving left)
FIG. 9 is a top view of the main parts of the relative position adjustment mechanism 400 illustrating the adjustment method of the second embodiment. For clarity, reference numerals are assigned only to FIG. 9B, and some parts are omitted in FIG. 9B. FIG. 9B is a top view illustrating a standard state in which the distance from the center O3 of the adjustment shaft 423 to the center line Ca of the sliding hole 421a is the same as the distance from the center O3 to the center line Cb of the sliding hole 421b. FIG. 9A is a top view illustrating a state in which the rotating plate 422 is rotated clockwise relative to the standard state, causing the sliding shaft 401a to slide toward one end of the sliding hole 421a and the sliding shaft 401b to slide toward the other end of the sliding hole 421b. In FIG. 9A, the adjustment shaft 423 has moved to the left in the adjustment direction 430.

(Move right)
9C is a top view showing a state in which the rotating plate 422 is rotated counterclockwise relative to the standard state, causing the sliding shaft 401a to slide to the other end of the sliding hole 421a and the sliding shaft 401b to slide to one end of the sliding hole 421b. In FIG. 9C, the adjustment shaft 423 has moved to the right in the adjustment direction 430.

After adjustment using the relative position adjustment mechanism 400, screws (not shown) are fastened into the screw holes 424a and 424b to fix the rotation adjustment unit 420. Note that when adjusted to the position shown in Figure 9(A) or 9(C), the screw holes are provided so that the screws can be fixed in that position.

By configuring as in Example 2, the adjustment shaft 423 can be moved along a single axis without affecting any direction other than the required direction. Specifically, the adjustment shaft 423 moves in the adjustment direction 430, and does not move in the direction of line L1. Furthermore, according to Example 2, movement in the adjustment direction 430 and the direction of line L1 other than rotation around the adjustment shaft 423 is restricted by the sliding shafts 401a and 401b and the sliding holes 421a and 421b, and is fixed without relying on frictional force caused by fastening screws. Therefore, the adjustment shaft 423 is less likely to shift in position due to a load applied thereto, and good image quality can be maintained after adjustment. Furthermore, in Example 2, the amount of movement of the adjustment shaft 423 changes continuously according to the amount of rotation of the rotation adjustment unit 420, allowing fine adjustments to be made to any positional deviations.

As described above, according to the second embodiment, misalignment in a printer system in which sheet feeding devices are stacked can be adjusted without being affected by the number of stacking levels.

[Relative position adjustment mechanism]
A third embodiment will now be described. Fig. 10 is a schematic diagram showing the configuration of a relative position adjustment mechanism 600, which is an adjustment unit of the third embodiment. In the third embodiment, the relative position adjustment mechanism 600 has a fitting hole unit 500 disposed on the bottom surface 252, which is the first bottom surface of the sheet feeding device 2, and a fixed shaft 501, which is a third shaft portion, protruding from the top surface 250, which is the second top surface of the sheet feeding device 2. The fitting hole unit 500 fits into the fixed shaft 501.

The configuration of the relative position adjustment mechanism 600 of Example 3 will be described. Figure 10(A) is a side view of the fitting hole unit 500 with the fixed shaft 501 inserted and positioned, and Figure 10(B) is a view of the fitting hole unit 500 from the bottom surface 252 side. The fitting hole unit 500 is composed of a bottom plate 520, which is the third member, and a movable plate 510, which is the fourth member. The movable plate 510 is fixed to the bottom plate 520 by screw fixing holes 511a and 511b.

The movable plate 510 has a third sliding hole, the elongated sliding hole 521a, and a fourth sliding hole, the elongated sliding hole 521b. The elongated sliding hole 521a is arranged so that its longitudinal direction is parallel to the second direction 531. The elongated sliding hole 521b is arranged so that its longitudinal direction is parallel to the second direction 531.

The bottom plate 520 has a sliding pin 512a, which is the third sliding shaft, and a sliding pin 512b, which is the fourth sliding shaft, protruding from the bottom plate 520. The sliding pin 512a protruding from the bottom plate 520 fits into the sliding elongated hole 521a, and the sliding pin 512b fits into the sliding elongated hole 521b, allowing them to slide in the up and down direction (second direction) in Figure 10 (B) while sliding.

The bottom plate 520 has a first elongated hole 513 extending along a first direction 530, along which the relative positions of the stacked sheet feeding device 2 and printer 1, or between the stacked sheet feeding devices 2, are adjusted. The elongated hole 513 is arranged so that its longitudinal direction is parallel to the horizontal first direction 530. Meanwhile, the movable plate 510 has an adjustment elongated hole 522, a second elongated hole that intersects with the first direction 530 at an angle θ of less than 90° (θ<90°). The fixed shaft 501 fits into the adjustment elongated hole 522 together with the elongated hole 513. In the third embodiment, the angle θ, which is the predetermined angle formed between the axis of the elongated hole 513 (first direction 530) and the axis of the adjustment elongated hole 522 (longitudinal direction), is set to, for example, 70°. This angle θ can be set anywhere within the range of 0°<θ<90°. The fitting hole unit 500 is positioned by restricting the fixed shaft 501 with four surfaces: the side surfaces 514a and 514b of the elongated hole 513 on the bottom plate 520, and the side surfaces 523a and 523b of the adjustment elongated hole 522 on the movable plate 510.

[Adjustment method]
Next, an adjustment method in Example 3 will be described. FIG. 11 is a top view of essential parts of the relative position adjustment mechanism 600 illustrating the adjustment method in Example 3. For clarity in FIG. 11, reference numerals are assigned only to FIG. 11B, and some parts are omitted in FIG. 11B as well. When screws (not shown) are loosened from the screw fixing holes 511a and 511b, the movable plate 510 is restricted by the sliding pins 512a and 512b and becomes movable in a second direction 531 perpendicular to the first direction 530. The adjustment slot 522 intersects with the first direction 530 at an angle θ. Therefore, when the movable plate 510 moves upward in FIG. 10B, the area formed by the side surfaces 514a, 514b, 523a, and 523b of the two slots (slot 513 and adjustment slot 522) shifts to the left in the figure. In other words, the position of the fitting hole unit 500 is adjusted to the right in the figure relative to the fixed shaft 501. Adjustment in the opposite direction can be performed using the same operation. By moving the movable plate 510 downward in Figure 10(B), the fitting hole unit 500 is adjusted to the left.

(Standard state, left movement when viewed from the bottom)
FIG. 11B is a bottom view showing a standard state in which the center O4 of the fixed shaft 501 coincides with the centers of the elongated hole 513 and the adjustment elongated hole 522, and the sliding pins 512a and 512b are located at the centers of the elongated sliding holes 521a and 521b in the second direction. In the standard state, a virtual line L2 passes through the center O4 of the fixed shaft 501 and is parallel to the second direction 531. FIG. 11A is a bottom view showing a state in which the movable plate 510 is moved upward in FIG. 11, causing the sliding pin 512a to slide toward one end of the elongated sliding hole 521a and the sliding pin 512b to slide toward one end of the elongated sliding hole 521b. In FIG. 11A, the fixed shaft 501 has moved leftward (leftward of the virtual line L2) relative to FIG. 11B.

(Movement to the right when viewed from the bottom)
Fig. 11C is a bottom view showing a state in which the movable plate 510 is moved downward in Fig. 11, so that the sliding pin 512a slides to the other end of the elongated sliding hole 521a and the sliding pin 512b slides to the other end of the elongated sliding hole 521b. In Fig. 11C, the fixed shaft 501 has moved to the right (right of the imaginary line L2) with respect to Fig. 11B.

In the first to third embodiments, the sheet feeding device of a printer is used for the explanation, but the present invention is not limited to this. The present invention can also be applied to other optional devices that are stacked on top of the image forming apparatus, such as a discharge unit, or other devices that are stacked on the image forming apparatus. Furthermore, the present invention is not limited to electrophotographic image forming apparatuses, and can also be applied to sheet feeding devices in inkjet image forming apparatuses, for example.
In addition, in Examples 1 to 3, a hole is provided through the bottom surface and a pin is provided through the hole in the bottom surface on the top surface, but this is not limited to this. A recess may be provided on the bottom surface and a protrusion that fits into the recess in the bottom surface on the top surface. Alternatively, a pin or a protrusion may be provided on the bottom surface and a hole or a recess may be provided on the top surface.

As described above, according to the third embodiment, misalignment in a printer system in which sheet feeding devices are stacked can be adjusted without being affected by the number of stacking levels.

2a, 2b Sheet feeding devices 41, 42 Positioning pins 43, 44 Positioning hole 200 Relative position adjustment mechanism 250b Top surface 252a Bottom surface

Claims (12)

a first device having a first top surface perpendicular to a vertical direction and a first bottom surface provided below the first top surface in the vertical direction and parallel to the first top surface;
a second device having a second top surface perpendicular to the vertical direction and a second bottom surface disposed below the second top surface in the vertical direction and parallel to the second top surface;
an image forming system including: the first device is stacked on the second device in the vertical direction, the second top surface faces the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material,
a positioning unit that determines a position of the first device when the first device is placed on the second device in a horizontal direction perpendicular to the vertical direction;
the positioning unit has an adjustment unit that adjusts a relative positional deviation between the first device and the second device in the horizontal direction,
the first bottom surface has a through hole;
the second top surface has a first axis portion parallel to the up-down direction,
the adjustment unit has a first member and a second member,
the first member has a first hole portion that fits into the first shaft portion, and at least three surfaces that surround the first hole portion and are parallel to the up-down direction,
the second member has at least three inner surfaces that contact the at least three surfaces, respectively, and an outer periphery that surrounds the at least three inner surfaces and fits into the through hole;
The image forming system, wherein the adjustment unit adjusts the positional deviation by changing a state of contact between the at least three surfaces and the at least three inner surfaces. the first member has four surfaces, a first surface, a second surface, a third surface, and a fourth surface, which are parallel to the up-down direction and surround the first hole portion,
the second member has four inner surfaces, namely, a first inner surface, a second inner surface, a third inner surface, and a fourth inner surface, which are in contact with the four surfaces, respectively;
2. The image forming system according to claim 1 , wherein the adjustment unit adjusts the positional deviation by changing a state of contact between the four surfaces and the four inner surfaces. the first surface has a first protruding surface that is farther from the center of the first hole portion than the first surface,
the third surface has a second protruding surface that is farther from the center of the first hole portion than the third surface,
a first distance from the center of the first hole portion to the first protruding surface, a second distance from the center of the first hole portion to the second surface, a third distance from the center of the first hole portion to the third surface, and a fourth distance from the center of the first hole portion to the fourth surface are all equal,
the first distance is longer than a fifth distance from the center of the first hole to the first surface;
3. The image forming system according to claim 2 , wherein the third distance is shorter than a sixth distance from the center of the first hole to the second protruding surface. 4. The image forming system according to claim 3 , wherein the sum of the first distance and the third distance is equal to the sum of the fifth distance and the sixth distance. a seventh distance from the center of the outer circumferential portion to the second inner surface and an eighth distance from the center of the outer circumferential portion to the fourth inner surface are equal,
a ninth distance from the center of the outer circumferential portion to the first inner surface is shorter than the seventh distance;
5. The image forming system according to claim 4 , wherein a tenth distance from the center of the outer periphery to the third inner surface is longer than the seventh distance. 6. The image forming system according to claim 5 , wherein a midpoint of the total distance of the ninth distance and the tenth distance is shifted toward the third inner surface side from the center of the outer periphery. The adjustment unit adjusts the first member and the second member by
a first adjustment position in which the first surface and the first inner surface are in contact with each other, the second surface and the second inner surface are in contact with each other, the third surface and the third inner surface are in contact with each other, and the fourth surface and the fourth inner surface are in contact with each other;
a second adjustment position in which the second member is rotated 90 degrees clockwise relative to a state in which the four surfaces are in contact with the four inner surfaces at the first adjustment position, so that the four surfaces are in contact with the four inner surfaces;
a third adjustment position in which the second member is rotated 90 degrees in the clockwise direction and the first member is rotated 90 degrees in the counterclockwise direction relative to a state in which the four faces and the four inner faces are in contact with each other at the first adjustment position, thereby bringing the four faces and the four inner faces into contact with each other;
a fourth adjustment position in which the second member is rotated 90 degrees counterclockwise relative to a state in which the four surfaces are in contact with the four inner surfaces at the first adjustment position, thereby bringing the four surfaces into contact with the four inner surfaces;
a fifth adjustment position in which the second member is rotated 90 degrees in the counterclockwise direction and the first member is rotated 90 degrees in the clockwise direction relative to a state in which the four surfaces are in contact with the four inner surfaces at the first adjustment position, thereby bringing the four surfaces into contact with the four inner surfaces;
It is possible to adjust
7. The image forming system according to claim 4 , wherein the first adjustment position, the second adjustment position, the third adjustment position, the fourth adjustment position, and the fifth adjustment position are positions in a predetermined direction in the horizontal direction. a first device having a first top surface perpendicular to a vertical direction and a first bottom surface provided below the first top surface in the vertical direction and parallel to the first top surface;
a second device having a second top surface perpendicular to the vertical direction and a second bottom surface disposed below the second top surface in the vertical direction and parallel to the second top surface;
an image forming system including: the first device is stacked on the second device in the vertical direction, the second top surface faces the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material,
a positioning unit that determines a position of the first device when the first device is placed on the second device in a horizontal direction perpendicular to the vertical direction;
the positioning unit has an adjustment unit that adjusts a relative positional deviation between the first device and the second device in the horizontal direction,
the first bottom surface has a first axis portion parallel to the up-down direction,
the second top surface has a through hole;
the adjustment unit has a first member and a second member,
the first member has a first hole portion that fits into the first shaft portion, and at least three surfaces that surround the first hole portion and are parallel to the up-down direction,
the second member has at least three inner surfaces that contact the at least three surfaces, respectively, and an outer periphery that surrounds the at least three inner surfaces and fits into the through hole;
The image forming system is characterized in that the adjustment unit adjusts the positional deviation by changing a state of contact between the at least three surfaces and the at least three inner surfaces. a first device having a first top surface perpendicular to a vertical direction and a first bottom surface provided below the first top surface in the vertical direction and parallel to the first top surface;
a second device having a second top surface perpendicular to the vertical direction and a second bottom surface disposed below the second top surface in the vertical direction and parallel to the second top surface;
an image forming system including: the first device is stacked on the second device in the vertical direction, the second top surface faces the first bottom surface, and the first device and the second device operate in cooperation to form an image on a recording material,
a positioning unit that determines a position of the first device when the first device is placed on the second device in a horizontal direction perpendicular to the vertical direction;
the positioning unit has an adjustment unit that adjusts a relative positional deviation between the first device and the second device in the horizontal direction,
the first bottom surface has a through hole;
the second top surface has a first sliding shaft and a second sliding shaft,
the adjustment unit has a second shaft portion that fits into the through hole, a rotating unit that rotates around the second shaft portion, a first sliding hole portion that is provided in the rotating unit and has a curved elliptical shape that fits onto the first sliding shaft, and a second sliding hole portion that is provided in the rotating unit and has a curved elliptical shape that fits onto the second sliding shaft,
the second sliding shaft and the second sliding hole portion are disposed at positions that are line-symmetrical with the first sliding shaft and the first sliding hole portion with respect to the second shaft portion, and have the line-symmetrical shape;
The image forming system is characterized in that the adjustment unit adjusts the positional deviation by rotating the rotation unit. the first device is an image forming device that forms an image on a recording material,
10. The image forming system according to claim 1 , wherein the second device is an optional device that operates in cooperation with the image forming device. the first device and the second device are optional devices that operate in cooperation with an image forming device that forms an image on a recording material,
10. The image forming system according to claim 1 , wherein one or more optional devices are disposed below the image forming apparatus in the vertical direction. the optional device is a feeding device that stores recording materials and feeds the recording materials to the image forming device,
12. The image forming system according to claim 10 , wherein the adjustment unit adjusts positional deviation in a direction perpendicular to a feeding direction in which the recording material is fed.