Image forming apparatus

Abstract

An image forming apparatus is provided that can guide the placement position of paper relative to a mounting stage even when the paper has an image formed on only one side. The image forming apparatus includes a mounting stage, an image forming unit, an image reading unit, and a position correction unit. The image forming apparatus places a paper with a first image formed on it on the mounting stage with the first side facing the mounting stage and the end of the paper away from the end of the mounting stage. When the image reading unit reads the end of the paper and the image formed on the first side of the paper while the paper is covered by a cover paper, and when a part of the paper is placed with a portion exposed from the mounting stage and the first edge of the cover paper, the image forming unit forms a third image on the first side of the paper, with the second image formed on the side of the cover paper opposite to the side in contact with the paper as the alignment target.

Description

Technical Field

[0001] This invention relates to an image forming apparatus. Background Technology

[0002] When determining the position of an image formed on paper relative to the paper, the end of the paper needs to be used as a reference for the measurement.

[0003] Reading images on paper involves using a stage (e.g., the glass stage of a flatbed scanner) and reading the image formed on the side of the paper facing the stage. However, if the paper is placed against the end of the stage for reading, the end of the paper cannot be accurately measured. Therefore, when determining the position of the image relative to the paper, the image needs to be read with the paper positioned away from the end of the stage, i.e., with a gap between the end of the stage and the paper.

[0004] On the other hand, if the paper is moved too far from the end of the stage, a portion of the paper may detach from the reading area on the stage.

[0005] Patent Document 1 proposes to use a cover paper to cover a paper placed on a mounting table, and to use an alignment image formed on the cover paper and an alignment image formed on the back side (i.e., the second side) of the paper facing the mounting table to adjust the paper's position relative to the mounting table.

[0006] Patent Document 1: Japanese Patent No. 5974699

[0007] If the proposal in Patent Document 1 is adopted, the paper can be placed at a predetermined position on the mounting stage. Therefore, the problem that part of the paper may detach from the reading area on the mounting stage is suppressed.

[0008] However, in the proposed method, images are formed on both sides of the paper, and when reading the image on the first side, the image on the second side is used for alignment. That is, images need to be formed on both sides of the paper.

[0009] However, there exist image forming apparatuses that, when forming images on both sides of a paper, are limited in length, for example, along the long side of the paper, such that on long sheets of paper exceeding this limit, images can only be formed on one side. The determination of the image position needs to be performed for each type of paper, and also for papers where images can only be formed on one side. Alternatively, there exist image forming apparatuses that inherently form images only on one side of the paper. Summary of the Invention

[0010] The object of the present invention is to provide an image forming apparatus that can guide the paper to a position relative to the mounting stage even when the paper has an image formed on only one side.

[0011] Solution 1 is an image forming apparatus, characterized by comprising: a stage for holding an object for reading an image; an image forming unit for forming an image on a first surface of a paper, including a first image for determining the relative position of the paper with respect to its end; an image reading unit for reading the image placed on the stage; and a position correction unit for correcting the relative position of the image formed on the paper with respect to the paper based on the reading result of the image reading unit, placing the paper with the first image formed on it facing the stage and at an end of the paper away from the stage, and when reading the image of the end of the paper and the image formed on the first surface of the paper by the image reading unit while the paper is covered by a cover paper, when a portion of the paper is placed with a portion exposed from the stage and the first edge of the cover paper, the image forming unit forms a third image on the first surface of the paper, with a second image for alignment formed on the side of the cover paper opposite to the side in contact with the paper as the alignment object.

[0012] Solution 2 is the image forming apparatus described in Solution 1, characterized in that the image forming unit, as the third image, forms both a first third image for alignment when the image reading unit reads an image formed in the region containing the first end of the paper and a second third image for alignment when the image reading unit reads an image formed in the region containing the second end of the paper on the first surface of the paper.

[0013] Solution 3 is the image forming apparatus described in Solution 2, characterized in that the image forming unit forms a first third image and a second third image that are visually distinct from each other on the first surface of the paper.

[0014] Scheme 4 is the image forming apparatus described in Scheme 3, characterized in that the first third image is an image composed of one shape disposed relative to the second image at a position facing away from the first edge, and the second third image is an image composed of two of the shapes disposed relative to the second image at a position facing away from the first edge and arranged in an orientation intersecting the first edge.

[0015] Solution 5 is the image forming apparatus according to any one of Solutions 1 to 4, characterized in that, in addition to the first image and the third image, the image forming unit forms a fourth image on the first surface of the paper, which is required to overlap with and intersect the first edge.

[0016] Solution 6 is the image forming apparatus described in Solution 5, characterized in that the image forming unit, as the fourth image, forms both a first fourth image for alignment in the orientation intersecting the first edge when the image reading unit reads an image formed in the region including the first end of the paper and a second fourth image for alignment when the image reading unit reads an image formed in the region including the second end of the paper on the first surface of the paper.

[0017] Solution 7 is the image forming apparatus according to any one of Solutions 1 to 6, characterized in that the image forming unit forms an image on a second paper, different from the first paper used to form an image containing the first image, for using the second paper as the cover paper.

[0018] Solution 8 is the image forming apparatus described in Solution 7, characterized in that the image forming unit forms an image of a color that can be distinguished from the color of the first paper at the portion overlapping with the end of the first paper when the first surface of the second paper is covered by the first paper, and forms the second image on the second surface of the second paper.

[0019] Solution 9 is the image forming apparatus described in Solution 7, characterized in that the image forming unit forms the second image, which is distinguishable from the color of the first paper, on a second paper of a color distinguishable from the color of the second paper.

[0020] Invention Effects

[0021] According to the first aspect of the image forming apparatus of the present invention, even paper with an image formed on only one side can be guided to a position relative to the mounting stage.

[0022] According to the second aspect of the image forming apparatus of the present invention, accurate measurement can also be performed on two regions of paper, including each end.

[0023] According to the third and fourth embodiments of the present invention, the image forming apparatus can easily determine which area of ​​the paper is being measured.

[0024] According to the fifth and sixth embodiments of the present invention, the image forming apparatus can easily place the paper in an accurate position compared to the case where the fourth image is not formed.

[0025] According to the seventh, eighth, and ninth embodiments of the present invention, the image forming apparatus can generate cover paper when needed. Attached Figure Description

[0026] The embodiments of the present invention will be described in detail with reference to the following figures.

[0027] Figure 1 This is an overall structural diagram of an image forming apparatus according to one embodiment of the present invention;

[0028] Figure 2 It is a diagram representing the image displayed on a touch panel-type display screen;

[0029] Figure 3 It is a diagram representing the image displayed on a touch panel-type display screen;

[0030] Figure 4 It is a diagram representing the covering paper;

[0031] Figure 5 This is a diagram showing the paper alignment during the reading of chart images;

[0032] Figure 6 It is a diagram representing a long sheet of paper containing the chart image of Example 2;

[0033] Figure 7 It refers to a large-sized sheet of paper containing charts or graphs;

[0034] Figure 8 This is a diagram showing the covering paper in example 2.

[0035] [Explanation of reference numerals in the attached figures]

[0036] 10-Image forming apparatus,

[0037] 10a - Paper output tray

[0038] 11K, 11C, 11M, 11Y - image retainers,

[0039] 100 - Image forming unit,

[0040] 200-Image Reading Unit

[0041] 250-Transparent Glass

[0042] 260-Top Cover,

[0043] 2701 - Display screen

[0044] 2702 - Button Group

[0045] 2702a - Calibration Calculation Mode Button

[0046] 4-Fixing device,

[0047] 5-Exposure Department

[0048] 400-length paper,

[0049] 400a-1st end,

[0050] 400b - Second end,

[0051] 500, 800 - Covering paper,

[0052] 503, 803 - Alignment images

[0053] 504-First Edge Part

[0054] 601, 602 - Images for detection

[0055] 603, 604, 605, 606 - Alignment images. Detailed Implementation

[0056] Figure 1 This is an overall structural diagram of an image forming apparatus according to one embodiment of the present invention.

[0057] The image forming apparatus is a copier that has both single-sided and double-sided output functions in addition to single-sided output.

[0058] The image forming apparatus 10 includes: an image reading unit 200 that reads an image on a sheet of paper and generates image data representing the image; an image forming unit 100 that forms the read image onto another sheet of paper based on the image data; and an operation unit 270 that receives various image forming information inputs from a user, such as specifying the number of output sheets, selecting double-sided / single-sided output, and specifying a tray for holding the paper before image output.

[0059] The operation unit 270 includes a touch panel-style display screen 2701 and a button group 2702 consisting of various buttons, such as a start button for commanding image reading and image formation, a value input button for inputting a specified number of output sheets, and control buttons for the image forming apparatus. The button group 2702 also includes a correction amount calculation mode button 2702a for setting the correction amount calculation mode in the image forming apparatus 10. This correction amount calculation mode calculates various correction amounts, such as the correction amount relative to the image forming position on the paper when forming an image on the paper, and the correction amount on the paper relative to the image magnification. The correction amount calculation will be described later.

[0060] The image reading unit 200 includes a top cover 260 that can be opened and closed by a user and a transparent glass 250 disposed directly below the top cover 260. The image reading unit 200 also includes elements for reading an image on paper below the transparent glass 250.

[0061] The image reading unit 200, as a component for performing image reading, includes a first reciprocating stage 210, a second reciprocating stage 220, a lens unit 230, and a CCD linear sensor 240. The first reciprocating stage 210 includes a first reflector 212 and a lamp 211 and is capable of moving along... Figure 1 The first reciprocating stage 210 functions to illuminate the image of the object being read through the lamp 211 and receive the reflected light. The second reciprocating stage 220 has a second reflector 221 and a third reflector 222 and, like the first reciprocating stage 210, is capable of moving in the left-right direction. The second reciprocating stage 220 and the lens 230 function to guide the reflected light received by the first reciprocating stage 210 to the CCD linear sensor 240. Furthermore, the CCD linear sensor 240 functions to receive the reflected light and generate image data representing the image.

[0062] Here, the image reading unit 200, as a reading mode for reading images on paper, has a transport reading mode and a stationary reading mode. In the transport reading mode, one sheet of paper 300 placed on the original document tray 261 is introduced at a time from the paper inlet 260a, and transported to the outlet 260b via a transport path indicated by a single-dot-dash arrow through a mechanism not shown. The transport reading mode is a reading mode in which the image on the transported paper is read using the stationary first reciprocating stage 210 and the paper is fed out to the output stage 262. The stationary reading mode is a reading mode in which the paper is stationary on the transparent glass 250 and read using the first reciprocating stage 210, which moves in the direction of the solid arrow in the figure. In the stationary reading mode, the surface of the transparent glass 250 facing the upper cover 260 becomes a platform for holding the paper 300 with the image to be read. Here, the upper cover 260 is opened, and the side of the paper 300 with the image to be read is facing... Figure 1 The paper 300 is placed on the transparent glass 250 with its lower side facing down, and the top cover 260 is placed on top, thereby pressing the paper 300 down from above. In the static reading mode, the first reciprocating stage 210 moves while illuminating the paper 300 on the transparent glass 250 and reading the image on the paper 300. As the first reciprocating stage 210 moves, the second reciprocating stage 220 also moves in the same direction at half the speed of the first reciprocating stage 210, so that the optical path length during the period from the reflected light from the paper to the CCD sensor 240 is always kept the same.

[0063] The image forming unit 100 includes image forming units 1K, 1C, 1M, and 1Y for forming images of each color: black (K), cyan (C), magenta (M), and yellow (Y), and an exposure unit 5 for irradiating a laser beam. Each of these image forming units 1K, 1C, 1M, and 1Y has an exposure unit 5 that irradiates a laser beam. Figure 1Electrophotographic image holders 11K, 11C, 11M, and 11Y are used for rotation in the directions of arrows Bk, Bc, Bm, and By. In addition to the image holders described above, each image forming unit also includes an electric charge generator (not shown) and a developer. The image holders in each image forming unit are charged by the electric charge generator (not shown) to a predetermined surface potential. The exposure unit 5 performs a raster scan along the rotation axis of the rotating image holders 11K, 11C, 11M, and 11Y using a laser beam, thereby forming an electrostatic latent phase based on the potential distribution on the image holders. The electrostatic latent phase is developed by electrostatically attaching a toner containing charged toner to the developer (not shown), thereby forming a toner-based developed image on the image holders.

[0064] Furthermore, in Figure 1 Each image forming unit 1 has a contacting element on its lower side that is along the edge of the image holding body. Figure 1 An intermediate transfer belt 2 moves in the direction of arrow A, and primary transfer rollers 110K, 110C, 110M, and 110Y are positioned opposite each image holder 11K, 110C, 110M, and 110Y across the intermediate transfer belt 2. The intermediate transfer belt 2 receives the transfer (primary transfer) of the developed image formed on each image holder and transports the primary transfer image.

[0065] Furthermore, in addition to the image forming units 1K, 1C, 1M, 1Y, the intermediate transfer belt 2, and the exposure unit 5, the image forming unit 100 is also equipped with a secondary transfer roller 3a for secondary transfer of the primary transfer image on the paper via the intermediate transfer belt 2, and a fixing device 4 for fixing the unfixed secondary transfer image transferred onto the paper. Near the intermediate transfer belt 2, a sensor 2a is provided to detect the inspection images of each color formed by each image forming unit and transferred onto the intermediate transfer belt 2 during the adjustment of the relative position and magnification between the primary transfer images from each image holder. During the adjustment of the relative position and magnification, the sensor 2a detects the inspection images of each color transferred onto the intermediate transfer belt 2, and based on the detection results, adjusts the image forming units 1K, 1C, 1M, and 1Y to make the relative position and magnification between the inspection images of each color appropriate.

[0066] Furthermore, the image forming unit 100 is also provided with three trays—a first tray 70A, a second tray 70B, and a third tray 70C—that respectively hold paper, and a drive roller 30 that drives the intermediate transfer belt 2. The intermediate transfer belt 2 receives driving force from the drive roller 30 while being tensioned to the drive roller 30 and other rollers, and travels along... Figure 1The intermediate transfer belt 2 moves cyclically in the direction of arrow A. The intermediate transfer belt 2 is pressed against the secondary transfer roller 3a by the support roller 3b. The primary transfer image on the intermediate transfer belt 2 is taken from any one of the first tray 70A, second tray 70B, and third tray 70C by the action of the secondary transfer roller 3a and transferred twice onto the paper being conveyed to the secondary transfer roller 3a. The paper that has received the second transfer is further conveyed and, through the fixing device 4, the second transfer image on the paper is fixed onto the paper and discharged onto the output tray 10. Here, a cleaning device 2b is provided near the intermediate transfer belt 2, and after the paper undergoes two transfers, the toner remaining on the intermediate transfer belt 2 is removed by the cleaning device 2b. Furthermore, the inspection images of each color formed on the intermediate transfer belt 2 during the adjustment of the relative position and magnification between the primary transfer images from each image holder are not transferred twice by the secondary transfer roller 3a but are removed by the cleaning device 2b.

[0067] The image forming apparatus 10 includes a controller 6 that controls each component within the image forming unit 100. The controller 6 includes an image reading memory 64 that stores image data generated by the CCD linear sensor 240 of the image reading unit 200. Furthermore, in the image forming apparatus 10, variations in paper feeding timing, paper type, and paper feeding path can cause deviations in the image forming position on the paper and changes in image magnification. Therefore, as will be described in detail later, in the image forming apparatus 10, a chart image is formed on the paper, and the image reading unit 200 reads the chart image on the paper (a detection image constituting the chart image), and various correction amounts are calculated, such as correction amounts for the image forming position relative to the paper and correction amounts for the magnification of the image on the paper. Therefore, in addition to the image reading memory 64, the controller 6 also includes a chart image memory 65 that stores chart image data representing the chart image used in the calculation of the correction amounts described later. The chart image memory 65 stores chart image data for each paper size. Furthermore, the controller 6 is also equipped with a cover paper memory 66 that stores data on the cover paper used when forming a chart image that is read and output onto paper. The cover paper memory 66 stores cover paper image data corresponding to the size of the paper used to form the chart image. The cover paper will be described later. Additionally, a first tray memory 61, a second tray memory 62, and a third tray memory 63 are provided to store calculated correction values. These correspond to the first tray 70A, the second tray 70B, and the third tray 70C, respectively. The reason for providing memory for storing correction values ​​for each tray is that the deviation of the image formation position on the paper and the degree of image magnification change will vary depending on the path the paper takes from the tray. Here, it is configured to pre-set which size or type of paper will be stored in each tray 70A, 70B, and 70C. Even when the power is turned on / off, the previous setting remains valid unless reset. Furthermore, the present invention can also include a structure for automatically detecting dimensions.

[0068] When forming an image on paper based on image data stored in the image reading memory 64, the controller 6 reads a correction amount from the memory corresponding to the tray specified by the user via the operation unit 270. Based on the read correction amount, various correction processes, such as image formation position correction and image magnification correction, are performed on the image data stored in the image reading memory 64. The exposure unit 5 then forms an electrostatic latent phase based on the image data for which the correction processes have been performed. In this embodiment, the correction amount for the first tray memory 61 and the second tray memory 62 consists of two types of correction amounts: a surface correction amount when forming an image on the surface of the double-sided output and a back correction amount when forming an image on the back side of the double-sided output. In the image formation specified for double-sided output, the image data representing the image on the surface where the image is first output is corrected based on the surface correction amount, and the image data representing the image on the back side where the image is second output is corrected based on the back correction amount. On the other hand, in image formation when single-sided output is specified, image data is corrected according to the surface correction amount. However, in this embodiment, the third tray 70C contains paper that would be too long to form images on both sides (here referred to as long-size paper). Therefore, only the surface correction amount is stored in the third tray memory 63.

[0069] Next, a series of operations in the image forming apparatus 10, from reading the image to forming the image on the paper, will be described. Here, the case of using the static reading mode will be used as an example.

[0070] If the user directs the face of the image containing the object to be read towards... Figure 1 Paper is placed between the transparent glass 250 and the top cover 260 in the downward direction. Then, via the operation unit 270, the tray for holding the paper used in image formation is specified, double-sided / single-sided output is selected, and the number of output sheets is specified. Pressing the command in the button group 2702 to start image reading / image formation start button (not shown) illuminates the paper 300 with light 211 from the first reciprocating stage 210. The light is reflected off the paper 300 via the transparent glass 250. The reflected light passes through the first reflecting mirror 212 of the first reciprocating stage 210, the second reflecting mirror 221 of the second reciprocating stage 220, and the third reflecting mirror 222, and is imaged onto the CCD linear sensor 240 via the lens unit 230. Figure 1In the image reading unit 200, the path of the light is shown by a dotted arrow. The first reciprocating stage 210 moves along the direction of the solid arrow (sub-scanning direction) within the image reading unit 200 while illuminating the light based on this lamp, and the second reciprocating stage 220 also moves in the same direction at half the speed of the first reciprocating stage 210. Thus, the entire image on the paper 300 is illuminated, and reflected light from any part of the image is imaged onto the CCD linear sensor 240 while maintaining a constant optical path length. Image data based on the reflected light of the entire image is generated by the CCD linear sensor 240. The generated image data undergoes various signal processing, such as analog-to-digital conversion, by a processing circuit (not shown), and is then sent to the controller 6 and stored in the image reading memory 64 within the controller 6. The user places the opposite side of the paper 300 or the side with the new image on the new paper on the transparent glass 250 and presses the start button, thereby repeating the generation of image data and the storage in the image reading memory 64.

[0071] The controller 6 reads correction values ​​from the memory corresponding to the designated tray in the first tray memory 61, the second tray memory 62, and the third tray memory 63, based on the read correction values, and performs various correction processes on the image data stored in the image data memory 64, such as image formation position correction and image magnification correction. Furthermore, the controller 6 forms an electrostatic latent image based on the corrected image data on the charged image holders 11K, 11C, 11M, and 11Y relative to the exposure unit 5. The formed electrostatic latent image is developed by the developer in each image forming unit using a developer containing a toner corresponding to the color of each image forming unit to form a developed image of that color. Thus, the developed images of each color formed in each image forming unit are sequentially transferred (single-transfer) onto the intermediate transfer belt 2 by the action of the primary transfer rollers 110K, 110C, 110M, and 110Y corresponding to each image holder, gradually overlapping to form a multi-color primary transfer image. Furthermore, the multi-color primary transfer image is conveyed to the secondary transfer roller 3a via the intermediate transfer belt 2. On the other hand, the paper in the designated trays of the first tray 70A, second tray 70B, and third tray 70C is taken out in response to the formation of the multi-color primary transfer image, conveyed by the first transport roller pair 41a and the second transport roller pair 41b, and its orientation is adjusted by the alignment roller pair 40. Furthermore, the paper is fed out by adjusting the timing of the alignment rollers 40 so that the primary transfer image on the intermediate transfer belt 2 reaches the position of the secondary transfer roller 3a, thereby conveying the paper to that position. The secondary transfer roller 3a then transfers (double-transfers) the aforementioned multi-color primary transfer image onto the fed-out paper. The paper receiving the double transfer is further conveyed by the conveyor belt 31, and the secondary transfer image on the paper is fixed by the fixing device 4. Figure 1 The paper transport path at this time is shown by a dotted arrow pointing to the right within the image forming unit 100. Furthermore, after the paper undergoes two transfers, the toner remaining on the intermediate transfer belt 2 is removed by the cleaning device 2b.

[0072] When single-sided output is selected, the paper passes through the paper transport path only once and is fixed twice in the fixing device 4, and then is directly discharged onto the output tray 10a via the feed roller pair 40a.

[0073] On the other hand, when bi-sided output is selected, after the paper is transferred and fixed twice on one side via the paper transport path indicated by the right-facing arrow, it does not move towards the feed roller pair 40a but passes between the first bi-sided transport roller pair 40b and is transported downwards via the path indicated by the downward-facing dotted arrow. Then, the rotation direction of the second bi-sided transport roller pair 40c is reversed and the paper transport direction turns upwards. It passes through the third bi-sided transport roller pair 40d and the fourth bi-sided transport roller pair 40e via the path indicated by the left-facing dotted arrow, and then moves towards the second transfer roller 3a again via the first transport roller pair 41a, the second transport roller pair 41b, and the registration roller pair 40. Here, during the period from when the paper is initially received for transfer by the second transfer roller 3a until it reaches the position of the second transfer roller 3a again, a new multi-color first transfer image is formed on the intermediate transfer belt 2 in the manner described above. Furthermore, when the paper reaches the secondary transfer roller 3a for the second time, the new multi-color primary transfer image is transferred a second time to the back side, i.e., the second side, opposite to the first side of the paper that received the second transfer. The new secondary transfer image on the second side is then fixed by the fixing device 4, and the paper with fixed images on both sides is discharged onto the output tray 10a. Here, after the second transfer is performed on the second side of the paper, the toner remaining on the intermediate transfer belt 2 is removed by the cleaning device 2b.

[0074] In addition, when the third tray 70C is specified during image output, it is not possible to specify two-sided output due to the limitation of the paper transport path length for two-sided output. Only single-sided output of the first side can be performed on the paper contained in the third tray 70C.

[0075] The above is an explanation of the operation of the image forming apparatus 10, in which an image is formed on a piece of paper from which an image is read.

[0076] In the above description, the case of using the static reading mode was used as an example. However, when the transport reading mode is used, it is the same as the image reading and image formation described above, except that the image is read on the paper being transported by the first reciprocating stage 210 which is in a static state.

[0077] Furthermore, in the above description, when correcting the image formation position within the paper, correction processing was performed on the image formation position relative to the image data. However, the present invention can also correct the image formation position within the paper instead of correcting the image data through data processing. For example, regarding the overall position correction of the image within the paper in the paper transport direction, it can also be performed by controlling the alignment roller pair 40 to change the timing of feeding the paper toward the secondary transfer roller 3a. Moreover, regarding the overall position correction of the image within the paper in the direction perpendicular to the paper transport direction, it can also be performed by controlling the exposure unit 3 to change the starting position of the electrostatic latent phase on each image holder in the direction perpendicular to the paper transport direction (the rotation axis direction of each image holder).

[0078] Here, in the image forming apparatus 10, images can be formed on paper larger than the size that the image reading unit 200 can read. Typically, the reading range of the image reading unit 200 is consistent with the length and width of the transparent glass 250 (i.e., the length and width of the stage). Even when outputting an image to paper larger than the length and width of the transparent glass 250 (i.e., the length and width of the stage), the same principle applies as when outputting an image to paper smaller than the length and width of the transparent glass 250; for example, it is desirable to output the image at a predetermined size (magnification) accurately to a predetermined position on the paper.

[0079] The following explains the calculation of correction values ​​for the position, magnification, etc. of images formed on paper.

[0080] In the image forming apparatus 10, the image position, magnification, and other correction amounts for the image are calculated using the black (K) image forming unit 1K, as described below. Furthermore, regarding the correction amounts when using image forming units of other colors such as cyan (C), magenta (M), and yellow (Y), these can be obtained from the correction amounts calculated using the black (K) image forming unit 1K by adjusting the relative positions and magnifications between the primary transfer images formed by the four color image forming units, including the black (K) image forming unit 1K.

[0081] In the image forming apparatus 10, by pressing Figure 1The correction amount calculation mode button 2702a in the operation unit 270 sets the correction amount calculation mode in the image forming apparatus 10. Here, in the image forming apparatus 10, the correction amount is calculated for each size of paper, and by pressing the correction amount calculation mode button 2702a, the correction amount calculation mode for each size of paper is switched. In addition, in the image forming apparatus 10, as long as the correction amount calculation mode button 2702a is not pressed, the normal mode for image reading and image forming in the above manner is set. The normal mode is the default mode when power is applied to the image forming apparatus 10.

[0082] The image forming apparatus 10 includes a function for calculating correction values ​​such as image forming position and image magnification on paper with dimensions larger than the transparent glass 250 (length and width of the stage). Here, there are two types of paper larger than the transparent glass 250. One is a "long-size paper" that can only be output from one side. The other is a paper that can be output from both sides but has dimensions approximately the same as or larger than the transparent glass 250 (hereinafter, this type of paper will be referred to as "large-size paper").

[0083] In this embodiment, it is set to be in Figure 1 The first tray 70A contains paper with dimensions smaller than 250 mm of transparent glass (referred to as "standard size paper"). The second tray 70B contains "large size" paper (e.g., A3 paper) that can be printed on both sides. The third tray 70C contains "long size paper" that can only be printed on one side. Below, we will first explain the case where the correction amount is calculated using the long size paper (which can only be printed on one side) contained in the third tray 70C.

[0084] As described above, in the image forming apparatus 10, the correction amount calculation is performed on a per-paper tray basis, that is, on a per-paper-size basis. Each time the correction amount calculation mode button 2702a is pressed, the system switches to the correction amount calculation mode for each paper tray (each paper size). Here, this is achieved by pressing the button only a preset number of times. Figure 1 The correction amount calculation mode button 2702a in the operation unit 270 is set in the image forming apparatus 10 to calculate the correction amount relative to the image forming position on the long paper contained in the third tray 70C.

[0085] Figure 2 It is a diagram representing the image displayed on a touch panel-type display screen.

[0086] When setting a mode that calculates correction amounts relative to the image formation position on the paper, the image magnification, etc., the Figure 2 The screen shown is displayed on Figure 1The touch panel-style display screen 2701 displays three tray designation buttons: a first tray designation button 2701e, a second tray designation button 2701f, and a third tray designation button 2701g, for designating the tray containing the paper for outputting chart images; a chart image output command button 2701a, for commanding the output of chart images; a read start button 2701b, for transmitting information from the user to the image forming apparatus 10 regarding reading chart images; a read end button 2701c, for transmitting information from the user to the image forming apparatus 10 regarding ending the reading of chart images; an ESC button 2701d, for returning from the correction amount calculation mode to the normal mode; and a cover paper output command button 2701h, for commanding the output of cover paper, as buttons that receive the user's finger contact. Here, in the mode for calculating the correction amount on the long-size paper, only the tray designation button corresponding to the tray containing the long-size paper can be selected, and the tray designation button corresponding to the tray not containing the long-size paper cannot be selected. In the embodiment described here, only the third tray 70C contains long-sized paper. Therefore, the first tray designation button 2701e and the second tray designation button 2701f, which correspond to the first tray 70A and the second tray 70BC, respectively, which do not contain long-sized paper, are shown here with dotted lines. This indicates that selection is not possible even if the user touches the tray with their finger.

[0087] To perform the correction calculation for long-sized paper, press the button corresponding to the container holding the long-sized paper. Figure 1 Next, press the third tray designated button 2701g corresponding to the third tray 70C, and then press the chart image output command button 2701a to execute the chart image output. By pressing the third tray designated button 2701g, the correction amount used when outputting the chart image is determined, and the value stored in [the relevant database] is used. Figure 1 The third tray uses the correction amount of memory 63. If the chart image output command button 2701a is pressed, then in Figure 1 In the image forming unit 100, from Figure 1 The chart image memory 65 reads chart image data representing the chart image corresponding to the long-size paper contained in the third tray 70C, and performs correction processing related to the image formation position, image magnification, etc., using the correction amount stored in the third tray memory 63 at the specified time. Then, based on the corrected chart image data, the chart image is output to the first side of the long-size paper. The image formation at this time is the same as the image formation when single-sided output is selected as described above.

[0088] Furthermore, a cover paper is used when reading the chart image. If the cover paper output command button 2701d is pressed, a cover paper for reading the chart image formed on the long paper (here, the paper contained in the second tray 70B) of the size corresponding to the long paper on which the chart image was output this time is output.

[0089] Figure 3 This refers to a diagram on a long sheet of paper containing a chart or image. Here, Figure 3 (A) shows the first side of the long sheet of paper. Figure 3 (B) shows the second side of the long-size paper.

[0090] In the image forming apparatus illustrated in this embodiment, due to the limitations of the double-sided output transport path, it is impossible to output long-sized paper 400 on both sides, as described above. Figure 3 As shown, only single-sided output, where an image is formed on only the first side 401, is possible. The second side 402 remains blank. (The last sentence appears to be incomplete and possibly refers to a setting or setting.) Figure 1 The controller 6 shown stores chart image data corresponding to each size of paper in its chart image memory 65. Furthermore, the third tray memory 63, corresponding to the third tray 70C containing the long-sized paper, stores correction values ​​for the image formed on the first side 401 of the long-sized paper 400. When forming a chart image on the long-sized paper 400, the long-sized paper chart image data stored in the chart image memory 65 is read and printed out by the image forming unit 100. The image reading unit 200 reads the printed chart and uses the read chart image data to generate correction values ​​for image forming position, magnification, etc., stored in the third tray memory 63. Figure 3 The long sheet of paper 400 shown is a chart printed out by the image forming unit 100 in this process.

[0091] The chart image output to the long-size paper 400 consists of detection images 601 and 602 and alignment images 603 and 604.

[0092] Images 601 and 602 used for detection, for example, are for measuring the... Figure 3 The images shown are used to detect information such as the image formation position by measuring distances d1, d2, etc., between the image and the end of the long sheet of paper 400. After the image data obtained by reading the detection images 601, 602 is input into the image reading memory 64 of the controller 6, the controller 6 measures the distances d1, d2, etc., and detects information such as the image formation position. Furthermore, based on the detected information, a correction amount is generated and stored in the third tray memory 63. These detection images 601, 602 are examples of the first image described in this invention.

[0093] Here, one of the detection images 601 and 602 is formed at a position biased towards the first end 400a of the long-size paper 400, and the other detection image 602 is formed at a position biased towards the second end 400b of the long-size paper 400.

[0094] Furthermore, alignment images 603 and 604 are alignment images of the long-size paper 400 when reading detection images 601 and 602. Among these alignment images 603 and 604, alignment image 603, formed near the first end 400a, is used for alignment when reading detection image 601 formed near the first end 400a. And alignment image 604, formed near the second end 400b, is used for alignment when reading detection image 602 formed near the second end 400b.

[0095] Figure 4 This is a diagram showing the covering paper. Here, Figure 4 (A) indicates the first side of the paper being covered. Figure 4 (B) indicates the second side of the covering paper. By pressing... Figure 2 The chart image output command button 2701a is shown. After outputting the chart image, pressing the cover paper output button 2701h outputs the cover paper 500. The cover paper 500 output by pressing the cover paper output button 2701h is a cover paper of a size suitable for reading the chart image immediately following the output. That is, in the case described here, the output reading configuration is formed on Figure 4 The cover paper 500 is the size used when detecting the chart images 601 and 602 on the long sheet of paper 400 shown. As described above, it is used for reading... Figure 4 The cover paper 500 used for detecting images 601 and 602 on the long sheet of paper 400 is a large sheet of paper contained in the second tray 70B. This allows for double-sided output of the large sheet of paper. Here, a uniform black image is formed on the entire first side 501 of the large sheet of paper. This is because, in order to identify the chart, i.e., the end of the long sheet of paper 400, the density difference between the background color and the background of the long sheet of paper 400 is increased using data read by the image reading unit 200. Furthermore, a alignment image 503 is formed on the second side 502. The alignment image 503 is formed at a position along the first edge 504 extending along the long side of the cover paper 500 and is located further inward than the second edge 505 extending along the width direction. The alignment image 503 corresponds to an example of the second image mentioned in this invention.

[0096] Furthermore, the chart image is used to detect the current positional deviation of the image on the paper, and it needs to be output each time a detection is performed. In contrast, the cover paper 500 is stored after each output, thus allowing for multiple reuses. Therefore, regarding the cover paper 500, there is no need to set up a cover paper output button 2701h, and it can be output separately. Alternatively, it can be used with the image forming apparatus 10 (see reference 10). Figure 1 (To be prepared separately.)

[0097] Figure 5 This is a diagram showing the paper alignment during the reading of chart images.

[0098] The Figure 5 schematically shown Figure 1 The image reading unit 200 of the image forming apparatus 10 shown.

[0099] exist Figure 5 (A) shows a state where a cover paper 500 is placed on the transparent glass 250 of the image reading unit 200. When the cover paper 500 is placed on the transparent glass 250, its first surface 501 (reference) is positioned so that... Figure 4 The cover paper 500 is placed on the transparent glass 250 with its entire black surface (first side 501) facing downwards. When placing the cover paper 500 on the transparent glass 250, its upper left corner abuts against the frame of the transparent glass 250. This uniquely sets the position of the cover paper 500 relative to the transparent glass. Furthermore, when placing the cover paper 500 on the transparent glass 250, it is positioned such that the first edge 504 on the side where the alignment image 503 is formed is the front side (lower side in the figure).

[0100] Next, as Figure 5 As shown in (B), the long sheet of paper 400 with the first end 400a of the chart image facing downwards (towards the transparent glass 250) is inserted under the cover paper 500, so that the long sheet of paper 400 is exposed from the first edge 504 of the cover paper 500. Then, as... Figure 5As shown in (C), the portion of the long sheet 400 exposed from the first edge 504 of the cover paper 500 is folded over to align the position of the long sheet 400 while confirming the alignment image 603. In this embodiment, as an example, the alignment image 603 is an image composed of a single black rectangle. Here, the alignment image 503 drawn on the cover paper 500 and the alignment image 603 drawn on the long sheet 400 are arranged at the same position along the direction of the first edge 504 of the cover paper 500. Then, these alignment images 503 and 603 are further arranged such that they are separated from the first edge 504 of the cover paper 500 by a visually approximate distance of approximately equal distance from the first edge 504. When the long sheet 400 is positioned in this position, the portion covered by the cover paper 500 of the long sheet 400 includes the end of the paper and is within the reading area.

[0101] Then, the long sheet of paper 400 is positioned in the aforementioned location and the top cover 260 is closed. Using the aforementioned static reading mode, an image of the portion of the long sheet of paper 400 covered by the cover paper 500 is read. In the image data obtained from the reading, a detection image 601 clearly shows the end of the portion of the long sheet of paper 400 covered by the cover paper 500 and the side of the first end 400a. Figure 1 In the controller 6 shown, based on the image data, the following is obtained: Figure 3 The distances d1, d2, etc. shown indicate the position and magnification required for detecting the image 601 relative to the end of the long sheet of paper 400.

[0102] Next, in the same manner as described above, the second end 400b side of the long sheet 400 is inserted under the cover paper 500, and the detection image 602 formed on the second end 400b side is read. The alignment markers at this time are the alignment image 503 on the cover paper 500 and the alignment image 604 on the long sheet 400, which consists of two black rectangles. Thus, by setting the alignment image 604 to be different from the other alignment image 603 (here, an image consisting of one black rectangle) (here, an image of two black rectangles arranged along the long side of the long sheet 400), it is easy to identify whether the image read this time is from the first end 400a side or the second end 400b side. Furthermore, the two alignment images 603 and 604 only need to be distinguishable from each other; there is no need for a difference in the number of images. For example, they can be characters such as "1" and "2," patterns of different shapes, or images of different colors.

[0103] Furthermore, regarding the detection images 601 and 602, they are configured to be at least partially different from each other, and are configured to be distinguishable from the image data obtained by reading whether they are the detection image 601 on the first end 400a side or the detection image 602 on the second end 400b side.

[0104] Therefore, the detection image 601 from the first end 400a side and the detection image 602 from the second end 400b side are read, and the distance from the end of the long sheet 400 is detected. In the controller 6, the position, magnification, etc., of the image formed on the long sheet 400 are calculated to determine how much they have deviated from a preset position, magnification, etc. This "deviation" refers to a deviation from the stored correction amount that cannot be adequately corrected using the correction amount stored in the third tray memory 63. Therefore, in the controller 6, based on the information indicating the "deviation," the correction amount stored in the third tray memory 63 is corrected to eliminate the "deviation," and the corrected amount is stored in the third tray memory 63 instead of the currently stored correction amount. The newly formed image on the long sheet then uses the new correction amount, thus becoming an image with the preset accurate position and magnification.

[0105] Figure 6 This is a diagram representing a long sheet of paper containing the chart image of Example 2. Here, only those related to... Figure 3 The differences in the charts and images shown are explained.

[0106] In the Figure 6 In addition to the two alignment images 603 and 604, the diagram shown also includes two alignment images 605 and 606. These two alignment images 605 and 606 are images composed of line segments extending along the width direction of the long sheet 400. These alignment images 605 and 606 are standard alignment images that provide an appropriate insertion depth when the long sheet 400 is inserted under the cover paper 500. That is, when the first end 400a of the long sheet 400 is inserted under the cover paper 500, alignment image 605 is inserted to the first edge 504 of the cover paper 500 (see reference). Figure 5 The overlapping positions. Since the alignment image 605 exists, it becomes clearer where it should be inserted. Figure 3 Similarly, in the case of the chart images shown, the alignment in the width direction, i.e., along the first edge 504, is performed based on the alignment image 503 of the rectangle on the cover paper 500 and the alignment image 603 on the long paper 400.

[0107] Similarly, when the second end 400b of the long sheet 400 is inserted under the cover sheet 500, the alignment image 606 is inserted to overlap with the first edge 504 of the cover sheet 500. Since the alignment image 606 exists, the optimal insertion point becomes clearer. Alignment in the width direction, i.e., along the first edge 504, is performed based on the rectangular alignment image 503 on the cover sheet 500 and the alignment image 604 on the long sheet 400.

[0108] As described Figure 6 As shown, both an alignment image for the insertion direction and an alignment image for the width direction can be formed, instead of forming an alignment image for visually estimating the position in the insertion direction or the position in the width direction.

[0109] Figure 7 It refers to a large-sized paper containing chart images. Figure 7 (A) indicates the first side of a large-size sheet of paper. Figure 7 (B) indicates the second side of a large-size paper.

[0110] In the formation of the Figure 7 The chart image on the first side 701 of the large-size paper 700 shown includes a detection image 710 and alignment images 711, 712, 713, and 714. Similarly, a chart image including a detection image 720 and alignment images 721, 722, 723, and 724 is also formed on its second side 702. To easily distinguish between the first and second sides, the alignment images 711 and 712 on the first side 701 are blacked-out rectangular images, while the alignment images 721 and 722 on the second side 702 are rectangular images with black borders. Apart from this, the chart images on the first and second sides are identical.

[0111] As mentioned above, in Figure 1 The second tray 70B of the image forming apparatus 10 shown contains a large-size sheet of paper. The large-size paper can be output from both sides, meaning images can be formed on both sides. Therefore, a chart image is formed on both sides of the large-size paper. When forming a chart image on the large-size paper, firstly, by pressing the correction amount calculation mode button 2702a only a preset number of times, a mode for calculating the correction amount relative to the image forming position on the large-size paper contained in the second tray 70B is set. This allows the button to be pressed... Figure 2 The state of the second tray designated button 2701f is shown. Therefore, the second tray designated button 2701f is pressed. Then, the state stored in the controller 6 (reference) is read. Figure 1The large-size paper chart image data stored in the chart image memory 65 is corrected by a correction amount on the first side of the second tray memory 62, and a chart image based on the corrected chart image data is formed on the first side. Similarly, the large-size paper chart image data stored in the chart image memory 65 is corrected by a correction amount on the second side of the second tray memory 62, and the alignment images 721 and 722 are changed to rectangular images with black borders. A chart image based on the corrected and changed chart image data is formed on the second side.

[0112] When reading the chart image formed on the large-size paper 700, a portion of the paper 700 is inserted under the cover paper in the same manner as when reading the chart image on the long-size paper 400. Here, the alignment images 711 and 721 of the first side 701 and the second side 702 correspond to those on the long-size paper 400. Figure 6 The alignment images 603 shown, and the alignment images 712 and 722 of the first side 701 and the second side 702 correspond to the long-size paper 400. Figure 6 The alignment image 604 is shown. Furthermore, the alignment images 713 and 723 of the first side 701 and the second side 702 correspond to those on the long sheet of paper 400. Figure 6 The alignment images 605 shown, and the alignment images 714 and 724 of the first side 701 and the second side 702 correspond to the long-size paper 400. Figure 6 The alignment shown is illustrated in image 606. (Repeated explanation omitted.)

[0113] When aligning the large-size paper 700, it is not necessary to fold the paper 700. When reading the first side 701, alignment images 721-724 for the second side 702 are used for alignment. When reading the second side 702, alignment images 711-714 for the first side 701 are used for alignment. In the case of the large-size paper 700, four readings are performed, consisting of reading the first end 700a side of the first side 701, reading the second end 700b side of the first side 701, reading the first end 700a side of the second side 702, and reading the second end 700b side of the second side 702.

[0114] Figure 8 This is a diagram showing the covering paper in example 2.

[0115] Figure 4 The cover paper 500 shown is a type of paper with a uniform black image formed on its entire first side 501 and a registration image 503 formed on its second side. In contrast, in the... Figure 8In the case of the cover paper 800 in the second example shown, only the alignment image 803 is formed on the other side (the first side) of the paper with a certain degree of density. The density of the cover paper 800 is such that when... Figure 5 When read in the manner shown, the density of the paper tip can be detected with sufficient accuracy. Furthermore, the alignment image 803 formed on the paper 800 is an image of density that can be clearly visually recognized on the paper. Additionally, the alignment image 803 is not limited to black; any image of density that shows a difference in density from the background color of the paper used for the chart can be used. If a special color image forming apparatus is available, the alignment image can also be formed on black paper using a white special color.

[0116] The cover paper 800 in the second example can also be used as a cover paper for reading chart images formed on one side in an image forming apparatus that can only output on one side.

[0117] According to the above embodiments, even when a graphic image is formed on only one side of the paper, the paper can be accurately aligned.

[0118] The embodiments of the present invention described above are provided for illustrative purposes. Furthermore, these embodiments do not encompass the entirety of the invention, nor do they limit the invention to the disclosed methods. It will be apparent to those skilled in the art that various modifications and variations will be readily understood. These embodiments were chosen and described to most readily explain the principles and applications of the invention. Thus, those skilled in the art can understand the invention through various modifications that are assumed to be optimized for specific uses of various embodiments. The scope of the invention is defined by the foregoing claims and their equivalents.

Claims

1. An image forming apparatus characterized by comprising: have: A stage for holding objects that are being read from images; The image forming unit forms an image containing a first image for determining the relative position with respect to the end of the paper only on the first side of the paper; The image reading unit reads the image placed on the mounting stage; and The position correction unit corrects the relative position of the image formed on the paper relative to the paper based on the reading results from the image reading unit. The paper on which the first image is formed is placed on the mounting table with its first side facing the mounting table and its ends away from the mounting table. When the image reading unit reads the ends of the paper and the image formed on the first side of the paper while the paper is covered by a cover paper, When a portion of the paper is placed with its surface exposed from the first edge of the mounting table and the cover paper, the image forming unit forms a third image on the first surface of the paper, which is the second image for alignment formed on the side of the cover paper opposite to the side in contact with the cover paper and the paper. The image forming unit also forms a fourth image on the first surface of the paper, in addition to the first image and the third image, which is required to overlap with and intersect the first edge.

2. The image forming apparatus according to claim 1, characterized in that, The image forming unit, as the third image, forms both a first third image for alignment when the image reading unit reads an image formed in the region containing the first end of the paper along its long side and a second third image for alignment when the image reading unit reads an image formed in the region containing the second end of the paper on the first surface of the paper.

3. The image forming apparatus according to claim 2, characterized in that, The image forming unit forms a first third image and a second third image that are visually distinct from each other on the first side of the paper.

4. The image forming apparatus according to claim 3, characterized in that, The first third image is an image composed of one shape positioned relative to the second image and facing away from the first edge. The second third image is an image composed of two of the shapes positioned relative to the second image and facing away from the first edge, arranged in an orientation that intersects with the first edge.

5. The image forming apparatus according to claim 1, characterized in that, The image forming unit, as the fourth image, forms both a first fourth image (which is aligned with the first edge when the image reading unit reads the image formed in the region containing the first end of the paper) and a second fourth image (which is aligned when the image reading unit reads the image formed in the region containing the second end of the paper) on the first surface of the paper.

6. The image forming apparatus according to any one of claims 1 to 5, characterized in that, The image forming unit forms an image on a second sheet, different from the first sheet that forms the image containing the first image, for using the second sheet as the cover paper.

7. The image forming apparatus according to claim 6, characterized in that, The image forming unit forms an image of a color that can be distinguished from the color of the first paper at the portion of the first paper that overlaps with the end of the first paper when the first side of the second paper is covered, and forms the second image on the second side of the second paper.

8. An image forming apparatus characterized by comprising: have: A stage for holding objects that are being read from images; The image forming unit forms an image containing a first image for determining the relative position with respect to the end of the paper only on the first side of the paper; The image reading unit reads the image placed on the mounting stage; and The position correction unit corrects the relative position of the image formed on the paper relative to the paper based on the reading results from the image reading unit. The paper on which the first image is formed is placed on the mounting table with its first side facing the mounting table and its ends away from the mounting table. When the image reading unit reads the ends of the paper and the image formed on the first side of the paper while the paper is covered by a cover paper, When a portion of the paper is placed with a portion exposed from the first edge of the mounting table and the cover paper, the image forming unit forms a third image on only the first surface of the paper, with the second image for alignment formed on the surface of the cover paper opposite to the surface in contact with the cover paper and the paper as the alignment object. The image forming unit forms the second image on the cover paper, which is distinguishable from the color of the first paper containing the first image, on the cover paper.

Images