JP2009258170A - Recording material moving device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the position of a recording material fall within a receiving range of a receiving device even when moving the recording material. <P>SOLUTION: In the state of inhibiting moving by a register roll 6, a transport part 3 takes out a plurality of paper sheets P from a tray 2 and transports the same, respectively, and the position averaging the respective positions of the plurality of paper sheets P measured by a CIS sensor 7 is stored as a reference position corresponding to the tray 2 in a storage part 13. A control part 12 discriminates a receiving device 14 on receiving an identification number from a connection detecting part 5, and reads the reference position corresponding to the tray 2 from which the paper sheet P is taken out by the transport part 3, cumulative number of times of using the tray 2 and the movable range of the paper sheet P and an oscillation width according to a combination of the receiving device 14 and the tray 2 from the storage part 13, and calculates the paper sheet position. The control part 12 moves the paper sheet P for a distance corresponding to a difference between the paper sheet position and the position measured by the CIS sensor 7 so that the position of the paper sheet P approaches the calculated paper sheet position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording material moving apparatus and an image forming apparatus.

  In the image forming apparatus, when the recording material is transported, the position of the recording material may be shifted due to a manufacturing error of the transporting device that transports the recording material or a variation in mounting accuracy with respect to the image forming apparatus. Therefore, a technique for measuring the position of the recording material before image recording and correcting the positional deviation has been developed. Patent Document 1 discloses a technique for moving a sheet to a reference position after abutting the sheet against a reference guide provided at the side end of the conveyance path as a technique for correcting misalignment. Patent Document 2 discloses a technique for controlling a movement amount to be moved to a predetermined reference position based on a deviation amount of a sheet detected by a deviation detection unit as a technique for correcting misalignment. Yes. Further, Patent Document 3 discloses a measurement technique in which accuracy is improved by using a moving average process in positional deviation correction.

JP-A-2005-206338 Japanese Patent No. 3769913 Japanese Patent No. 4033233

  By the way, if the recording material is moved to a certain reference position by the above-described misregistration correction, in the recording material transfer process, the side edge of the recording material passes through the same position of the transfer device many times, or the recording material is recorded. Even in the fixing process of the toner image transferred and recorded on the material, the side edge of the recording material passes through the same position of the fixing device many times. As a result, for example, the position on the surface of the fixing roll included in the fixing device is scratched, or even if the scratch is not scratched, some marks remain at the position, so that the toner image has an influence such as uneven fixing. May occur. Therefore, in order to reduce such an effect, a technique is adopted in which the position of the side edge of the recording material is gradually moved within a predetermined range around the reference position every time an image is formed on the recording material. . This technique is called, for example, oscillation.

By the way, the image forming apparatus may be connected to a large-capacity storage device that stores a large amount of recording material on which an image is formed, a post-processing device that performs post-processing such as stapling on the recording material, and the like. is there. Hereinafter, these devices are referred to as receiving means in the sense of receiving a recording material on which an image is formed. When such a receiving means is connected to the recording material discharge portion in the image forming apparatus, the recording material can be discharged in the image forming apparatus within a range in which the receiving means can receive the recording material due to mechanical restrictions or the like. May be different from range. Here, the “range” refers to a length in a direction parallel to the recording surface of the recording material and perpendicular to the transport direction. If the recording material is discharged to a range where the receiving means cannot accept the recording material, the recording material will be discharged poorly. Therefore, in the oscillation, the recording material may be moved over a desired range around the reference position. There are cases where it is impossible.
An object of the present invention is to keep the position of a recording material within a range that can be received by a receiving means even when the recording material is moved.

  In order to solve the above-described problem, a recording material moving device according to claim 1 of the present invention records the recording material on the upstream side in the conveyance direction of the recording material from a recording position where an image is recorded on the recording material. Moving means for moving in a direction parallel to the surface and perpendicular to the conveying direction; and determining means for determining whether or not there is a receiving means for receiving a recording material on which an image is recorded at the recording position after being moved by the moving means; A reference position specifying means for specifying a reference position as a reference when the moving means moves the recording material, and a moving width when the recording material is moved by the moving means depending on the presence or absence of the receiving means. The width storage means stored in association with each other and the movement width corresponding to the presence / absence of the receiving means determined by the determination means are read from the width storage means and the recording material is moved. , Characterized by comprising a movement control means for moving the recording medium by said moving means in the range of the movement width of the reference position as a reference.

  According to a second aspect of the present invention, there is provided the recording material moving device according to the first aspect, wherein the width storage means stores the movement width in association with each of the receiving means, and the determination means includes: The receiving means determined to be present is identified, and the movement control means reads out a moving width corresponding to the receiving means identified by the determining means from the width storage means, and whenever the condition for moving the recording material is satisfied The recording material is moved by the moving means within a range of the moving width with reference to the reference position.

  According to a third aspect of the present invention, there is provided the recording material moving apparatus according to the second aspect, wherein the recording material is taken out from any of a plurality of storage means for storing the recording material and the plurality of storage means. Transport means for transporting to a position, and the reference position specifying means is transported by the transport means and storage means for storing the reference position determined for each storage means in association with each of the storage means. Specifying means for specifying the reference position stored in association with the storage means storing the recording material to be stored, and the width storage means is associated with the set of the receiving means and the storage means A movement width is stored, and the movement control means stores the movement width corresponding to a set of a receiving means identified by the determination means and a storage means storing a recording material conveyed by the conveyance means. Means Reading, each time satisfies moving the recording material, and wherein the moving the recording medium by said moving means in a moving range of said predetermined fixed width centered on the reference position.

  According to a fourth aspect of the present invention, there is provided the recording material moving apparatus according to the third aspect, wherein the recording material moving device measures a position in a direction parallel to the recording surface of the recording material conveyed by the conveying means and perpendicular to the conveying direction. And the reference position is a state in which movement of the recording material by the moving means is prohibited, and a plurality of recording materials are taken out from the storage means by the conveying means and respectively conveyed, and the plurality of recording materials are It is calculated from each position measured by the measuring means.

  According to a fifth aspect of the present invention, there is provided the recording material moving device according to the fourth aspect, further comprising a detection unit that detects that the storage unit is mounted at a mounting position of the storage unit. When the detecting means detects that the recording material is mounted, the recording means removes a plurality of recording materials from the storage means by the conveying means in a state where the movement of the recording material by the moving means is prohibited, and the plurality of recording materials are conveyed. The reference position calculated from each position measured by the measurement means for the material is written and stored in the storage means as a reference position corresponding to the storage means.

  According to a sixth aspect of the present invention, in the recording material moving device according to any one of the third to fifth aspects, the storage means records one surface of the recording material as the reference position. A first reference position when transporting as a surface and a second reference position when reversing the recording material and transporting the other surface as a recording surface are stored in association with the storage means, The specifying means has a first reference position when the conveying means conveys the one surface of the recording material as the recording surface, and a second reference position when the conveying surface conveys the other surface as the recording surface. It is specified as a reference position corresponding to the storage means in which the recording material is stored.

  According to a seventh aspect of the present invention, there is provided a recording material moving device according to the first or second aspect, wherein the recording material moving device has a plurality of conveyance paths, and the recording material is transferred via any one of the plurality of conveyance paths. Conveying means for conveying the recording material to a recording position where an image is recorded is provided, and the reference position specifying means stores the reference position determined for each of the conveying paths in association with each of the conveying paths. The storage means and a specifying means for specifying a reference position stored in the storage means in association with a conveyance path of a recording material conveyed by the conveyance means.

  An image forming apparatus according to an eighth aspect of the present invention includes the recording material moving device according to any one of the first to seventh aspects, and an image forming unit that forms an image at a position corresponding to the reference position. It is characterized by.

  An image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to the eighth aspect, wherein the image forming unit includes: an image holding body that holds an image; and a position of the image holding body according to the reference position. An image writing means for writing an image on the recording medium, and a transfer means for transferring and recording the image on the recording material.

According to the first aspect of the present invention, the position of the recording material to be moved can be within an appropriate range depending on the presence or absence of the receiving means.
According to the invention which concerns on Claim 2, the position of a recording material can be stored in the range which each receiving means can accept.
According to the invention of claim 3, when the reference position is specified according to the storage means, the range in which the receiving means can accept the position of the recording material according to the combination of the storage means and the receiving means. Can fit inside.
According to the fourth aspect of the present invention, it is possible to specify an appropriate reference position for each storage means as compared with the case of correcting according to one reference position regardless of which storage means the recording material is taken out from. it can.
According to the fifth aspect of the present invention, when the storage means is mounted at the mounting position of the storage means, the reference position corresponding to the storage means can be specified.
According to the invention of claim 6, when the conveying means conveys one surface of the recording material as a recording surface, and when the recording material is reversed and the other surface is conveyed as the recording surface, respectively. A suitable reference position can be specified.
According to the seventh aspect of the present invention, when the reference position is specified according to the conveyance path, the range in which the receiving means can accept the position of the recording material according to the combination of the conveyance path and the receiving means. Can fit inside.
According to the eighth aspect of the present invention, the position of the recording material falls within a range that can be received by the receiving device in accordance with the presence or absence of the receiving means, and an image can be formed on the recording material.
According to the ninth aspect of the invention, the effect of the eighth aspect can be obtained in an electrophotographic image forming apparatus.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
(A) Configuration (A-1) Overall Configuration of Image Forming Apparatus FIG. 1 is an explanatory diagram illustrating a schematic configuration example of the image forming apparatus 1. The image forming apparatus 1 shown in the figure forms an image on a recording material and outputs it. Here, examples of the recording material include paper such as plain paper or recycled paper, and a resin material such as an OHP sheet. In the present embodiment, description will be made using “paper P” which is an example of a recording material.

  The image forming apparatus 1 includes trays 2 a, 2 b, 2 c (hereinafter simply referred to as a tray 2 when not distinguished from each other) as an example of a plurality of storage units that store the paper P, and the paper P taken out from one of the trays 2. As an example of an image forming unit that forms a plurality of toner images corresponding to each of a plurality of color components such as YMCK on an image holding member such as a photosensitive member, as a conveying unit that conveys the toner to a recording position. Image forming units 4Y, 4M, 4C, 4K (hereinafter referred to simply as image forming unit 4 when these are not distinguished, the symbols Y, M, C, K represent yellow, magenta, cyan, and black toners, respectively. Each toner image formed by each image forming unit 4 is superimposed and transferred, and is conveyed by the conveyance unit 3 at the recording position. And an intermediate belt 9 as an example of a transfer unit for transferring the recording to come sheet P. Further, the image forming apparatus 1 can be connected to receiving devices 14a and 14b (hereinafter, simply referred to as receiving device 14 when they are not distinguished) as an example of a receiving unit that receives a sheet on which an image is formed. The receiving device 14 is, for example, a large-capacity storage device that stores a large amount of recording material on which an image is formed, or a post-processing device that performs post-processing such as stapling on the recording material. At a position where the receiving device 14 is connected to the image forming apparatus 1, it is detected that the receiving device 14 is connected, and identification information indicating the receiving device 14 is output, and image recording is performed on the receiving device 14. A connection detection unit 5 for discharging the subsequent paper P is provided. That is, the connection detection unit 5 is an example of a determination unit that determines whether or not there is a reception unit and identifies the reception unit that has been determined to be present.

Then, on the upstream side of the recording position in which the toner image is recorded on the paper P in the transport direction of the paper P, the registration roll 6 that transports the paper P to the recording position, and parallel to the surface of the paper P and in the transport direction A CIS (Contact Image Sensor) sensor 7 as an example of a measuring means for measuring a position in a perpendicular direction is disposed. The registration roll 6 has a configuration corresponding to an example of a moving unit that moves the paper P in a direction parallel to the surface and perpendicular to the transport direction. Here, the term “right angle” includes a strict “right angle” in a mathematical sense, and also includes an angle that can be regarded as a substantially right angle within a range of error in machine accuracy.
The image forming apparatus 1 includes an image reading unit 8 that optically reads and acquires image data based on the image forming unit 4 from a document, and a user interface unit (not shown).
In the embodiment, the trays 2a, 2b, and 2c, which are built-in trays, are exemplified as an example of a plurality of storage units that store the paper P. However, the storage unit is not limited to the built-in tray. An external option tray or a manual feed tray may be used.

(A-2) Functional Configuration of Image Forming Apparatus FIG. 2 is an explanatory diagram illustrating a functional configuration example of the image forming apparatus 1. As shown in the figure, the image forming apparatus 1 includes a CIS sensor 7, a control unit 12, a storage unit 13, a registration roll 6, an image reading unit 8, a conveyance unit 3, an image forming unit 4, and connection detection. Part 5.
The transport unit 3 takes out the paper P from one of the trays 2 and transports the paper P from the intermediate belt 9 to a recording position where the toner image is recorded on the paper P.
The CIS sensor 7 measures a position in a direction parallel to the surface of the paper P conveyed by the conveyance unit 3 and perpendicular to the conveyance direction, and supplies the obtained position information to the control unit 12.
The connection detection unit 5 detects that any receiving device 14 is connected, and outputs identification information indicating the receiving device 14 to the control unit 12.
The storage unit 13 is a storage device such as a hard disk drive or a flash memory. The storage unit 13 is an example of a storage unit that stores a reference position determined for each tray 2 that stores the paper P as a position in a direction parallel to the surface of the paper P and perpendicular to the transport direction at the recording position. The reference position is a position in a direction parallel to the surface of the paper P and perpendicular to the transport direction, and is a position where the transport of the paper P by the transport unit 3 is high. This reference position is stored in association with the tray 2 as a reference position table 131 as shown in FIG. The reference position table 131 describes “cumulative number” obtained by accumulatively adding the number of sheet conveyances for each tray 2. For example, when the image forming apparatus 1 is manufactured, or when the image forming unit 4 or the intermediate belt 9 is replaced, the cumulative number corresponding to all trays 2 is reset (that is, 0 is stored). ) Further, when any tray 2 is added or replaced, the cumulative number corresponding to that tray 2 is reset.
The storage unit 13 stores in advance a parameter group 132 and a computer program, which are a plurality of parameters necessary for processing in the control unit 12. FIG. 3B shows an example of the parameter group 132. The parameter group 132 includes an upper limit and a lower limit of a movable range determined in advance for each type of receiving device 14 being connected (including the case where none of the receiving devices 14 are connected, the same applies hereinafter), and being connected. A predetermined oscillation width is included for each combination of the receiving device 14 and the tray 2 to be used. The movable range is a range in which the paper P can be moved in a direction parallel to the surface and perpendicular to the transport direction. The oscillation width is a width in which the paper P is periodically moved in a direction parallel to the surface and perpendicular to the transport direction in order to protect the transfer device and the fixing device.
In addition to this, the storage unit 13 stores the sheet position interval, which is the interval between the sheet positions for moving the sheet P over the oscillation width, and the sheet position until the sheet position for moving the sheet P is updated. A numerical value necessary for processing, such as a count threshold that is the number of times of conveyance, is stored. In the present embodiment, the sheet position interval is 0.5 mm, and the frequency threshold is 100 times.

  The control unit 12 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and reads and executes a computer program stored in the storage unit 13 to execute the image forming apparatus. 1 part is controlled. In addition, the control unit 12 reads the reference position corresponding to the tray 2 from which the paper P has been taken out from the reference position table 131 of the storage unit 13, and also reads the parameter group 132 and the like of the storage unit 13, and based on these, the paper The position of the side edge of the sheet when the sheet is conveyed to the recording position (hereinafter referred to as the sheet position) is calculated. Then, according to the difference between the sheet position and the position measured by the CIS sensor 7 so that the position of the sheet P approaches the sheet position upstream of the recording position of the intermediate belt 9 in the conveyance direction of the sheet P. Find the correction amount. Then, the control unit 12 gives an instruction to the registration roll 6 so as to perform the correction process of the obtained correction amount.

The registration roll 6 is a roll pair composed of two rolls. The registration roll 6 is instructed by the control unit 12 with the paper P sandwiched between the roll pair on the upstream side of the recording position of the intermediate belt 9 in the paper transport direction. The sheet P is moved in a direction parallel to the surface and perpendicular to the transport direction by the correction amount. The shafts of the roll pair are connected to a drive mechanism including a motor and various gears. The amount of movement of the registration roll 6, that is, the amount of movement of the paper P is determined by the amount of rotation of the motor.
In accordance with an instruction from the control unit 12, the image forming unit 4 adjusts the writing position of the latent image for forming the toner image to a position corresponding to the paper position calculated by the above processing.

(A-3) Configuration of CIS Sensor and Registration Roll FIG. 4 is an explanatory diagram showing a configuration in the vicinity of the CIS sensor 7 and the registration roll 6. 4A shows the CIS sensor 7 and the registration roll 6 so that the paper conveyance direction is upward from the upper side in FIG. 1, that is, from the surface on which the toner image is recorded on the paper P (hereinafter referred to as an image forming surface). FIG. FIG. 4B is a view of the CIS sensor 7 as viewed from the upstream side in the paper conveyance direction.

  As shown in FIG. 4A, both the CIS sensor 7 and the registration roll 6 are provided upstream of the recording position of the toner image on the paper P in the paper transport direction. The registration roll 6 is located upstream of the CIS sensor 7 in the paper conveyance direction. The CIS sensor 7 is located on the left end side of the paper P when the image forming surface of the paper P is viewed so that the paper conveyance direction is upward. Further, the CIS sensor 7 is disposed so as to be offset toward one side of the conveyance path of the paper P in order to detect the side edge position of the paper P. The detection width of a predetermined size is provided in a direction parallel to the surface of the sheet and perpendicular to the transport direction so that the single CIS sensor 7 can cope with the size of the sheet.

  As such a CIS sensor 7, as shown in FIG. 4B, 1216 light receiving elements 7a1 to 7a1216 (hereinafter simply referred to as light receiving element 7a when not distinguished from each other) are parallel to the surface of the sheet and in the conveying direction. Are arranged in a direction perpendicular to the axis. Then, when the irradiation light from a plurality of light sources such as LEDs arranged along the direction in which the light receiving elements 7a are arranged is reflected by an object to be detected such as paper, the reflected light is received by the light receiving element 7a. It is configured. In the CIS sensor 7, the resolution at the time of measurement is specified by the number of light receiving elements 7a. In the present embodiment, the CIS sensor 7 has a maximum measurement width of 103 mm and 1216 pixels in the right direction in FIG. 4B, which is the direction intersecting with the paper conveyance direction from the origin O shown in FIG. 4B, and within the maximum measurement width. It has a resolution of 300 dpi.

  Here, the position where the registration roll 6 is sandwiched to move the paper P is the leading end side (that is, the downstream side) in the paper transport direction as shown in FIG. On the other hand, when the registration roll 6 sandwiches the paper P, on the rear end side (that is, the upstream side) of the paper P in the paper transport direction, a paper holder that cannot be released due to the mechanism in the transport unit 3 (such as a retard roll for preventing double feed) ) May exist. For this reason, the registration roll 6 must move the paper P in a direction parallel to the paper surface and perpendicular to the transport direction while the trailing edge of the paper is held by the paper holder. At this time, if the movement amount by which the registration roll 6 moves the paper P is large, the paper P is twisted, causing problems such as damage to the paper P, skew, and transfer failure. Therefore, the movement amount should be as small as possible. Is desirable.

(B) Operation (B-1) Reference Position Calculation Operation Next, the reference position calculation operation will be described. As described above, the storage unit 13 stores the reference position for each tray 2. The process of calculating and writing the reference position of each tray in the storage unit 13 is performed, for example, by the control unit 12 when the image forming apparatus 1 is shipped.
FIG. 5 is a flowchart for explaining the flow of operations for calculating the reference position.
First, the control unit 12 turns off the driving of the registration roll 6 that moves the paper P in a direction parallel to the surface and perpendicular to the transport direction, and prohibits the movement of the paper P in the above direction by the registration roll 6 ( Step SA001). Next, the control unit 12 refers to the storage unit 13 to determine whether or not the reference position is stored for all trays (step SA002). If it is determined that the reference positions are stored for all trays (step SA002; YES), the control unit 12 ends the reference position calculation operation.

  On the other hand, when it is determined that the reference positions are not stored for all the trays (step SA002; NO), the control unit 12 specifies the tray 2 in which the reference positions are not stored (step SA003), and calculates the reference position. “0” is stored as the number of times of measurement (step SA004). Next, the control unit 12 compares the number of times with a threshold value stored in advance in the storage unit, and determines whether the number of times is less than the threshold value (step SA005). As a result, when it is determined that the number of times is less than the threshold (step SA005; YES), the control unit 12 takes out the paper P from the tray 2 by the transport unit 3 and transports it, and transports the paper P by the CIS sensor 7. The position in the direction perpendicular to the direction is measured (step SA006). And the control part 12 memorize | stores the acquired measurement position in the memory | storage part 13 (step SA007), and increases the frequency | count 1 (step SA008). Thus, when steps SA005 to SA008 are repeated and the number of times becomes equal to or greater than the threshold (step SA005; NO), the control unit 12 calculates an average value based on an arithmetic average of the measurement positions stored in the storage unit 13, and this average value Is stored as the reference position of the tray 2 (step SA009). Thereafter, the control unit 12 returns the process to step SA002 and makes the above-described determination. For example, if the threshold value is 3, the control unit 12 performs measurement when the number of times is 0, 1, or 2 in step SA005 (step SA006). The average value is calculated. That is, the position of the tray 2 is measured as many times as indicated by the threshold value.

For example, in the calculation of the reference position with respect to the tray 2a, the sheet P is conveyed three times in a state where the movement of the sheet P by the registration roll 6 is prohibited. Since “5.2 mm”, “5.8 mm”, and “5.5 mm” are stored as the measurement positions, “5.5 mm” calculated as an average value is stored as shown in FIG. That is, it is written in the storage unit 13 as a reference position corresponding to the tray 2a. Note that these measurement positions are distances measured from the origin O shown in FIG. 4B to the right in the figure, which is the direction intersecting the paper conveyance direction, and were not received by the light receiving element 7a that received the reflected light. It is measured by the position that becomes the boundary of the light receiving element 7a.
This reference position is the average of the positions measured by the CIS sensor 7 when the transport unit 3 actually picks up the paper P from the specific tray 2 and transports it. The position transported by the transport unit 3 is likely to be a position close to this reference position. As a method for calculating the reference position, not only simply averaging the positions measured a plurality of times as in the present embodiment, but also averaging the remaining measurement values excluding the maximum and minimum values, or other measurement values Alternatively, a method may be used in which the remaining values excluding outliers are averaged.

(B-2) Operation of Image Pre-Processing Next, the operation of image pre-processing will be described. FIG. 6 is a flowchart for explaining the operation flow of the image formation pre-processing. First, when there is an image formation instruction from the user, the control unit 12 receives an identification signal indicating the connected receiving device 14 from the connection detecting unit 5 and identifies the type of the receiving device 14 (step SA101). Next, the control unit 12 determines the tray 2 from which the paper P is taken out (step SA102), and reads and determines the reference position corresponding to the tray 2 from the reference position table 131 of the storage unit 13 (step SA103). Next, the control unit 12 refers to the movable range from the parameter group 132 of the storage unit 13 (step SA104), and determines whether or not the reference position is within the movable range (step SA105). If it is determined that the reference position is not within the movable range (step SA105; NO), a predetermined error process is performed and the process is terminated (step SA106). The reference position is not within the movable range when, for example, the movable range is 2 to 10 mm, whereas the reference position is 1.5 mm. The predetermined error process at this time is, for example, a process of displaying a warning text on a display unit (not shown). On the other hand, if it is determined that the reference position is within the movable range (step SA105; YES), the control unit 12 takes out the connected receiving device 14 and the paper P from the parameter group 132 of the storage unit 13 in the tray 2. The oscillation width corresponding to the combination is read out to determine the oscillation range (step SA107), and image forming processing is performed (step SA300).

(B-3) Oscillation Range Determination Operation Here, the oscillation width corresponding to the combination of the receiving device 14 being connected to the image forming apparatus 1 and the tray 2 for taking out the paper P will be described with reference to FIG. FIG. 7A is a diagram illustrating an oscillation range in each tray 2 when the receiving device 14 is not connected to the image forming apparatus 1. FIG. 7B is a diagram illustrating an oscillation range in each tray 2 when the receiving device 14 a is connected to the image forming apparatus 1, and FIG. 7C is a diagram illustrating the receiving device 14 b in the image forming apparatus 1. It is a figure which shows the oscillation range in each tray 2 when is connected. When the receiving device 14 is not connected to the image forming apparatus 1, the upper limit of the movable range is set to 10.0 mm and the lower limit is set to 1.0 mm as shown in FIG. The oscillation width is set to 2.0 mm for the tray 2a and 4.0 mm for the tray 2b and the tray 2c. At this time, for example, the reference position corresponding to the tray 2a is 5.5 mm as shown in FIG. 3A, so the oscillation range is 4.5 to 6.5 mm.

  On the other hand, when the receiving device 14a is connected to the image forming apparatus 1, the upper limit of the movable range is set to 9.0 mm. Therefore, as shown in FIG. 7B, the upper limit of the movable range is located within the range of the oscillation width of the tray 2c when the receiving device 14 is not connected to the image forming apparatus 1, and the tray Unless the oscillation width of 2c is reduced, the oscillation width of the tray 2c exceeds the movable range. In order to prevent this, in the parameter group 132 of the storage unit 13, when the receiving device 14a is connected to the image forming apparatus 1, the oscillation width of the tray 2c is set to 2.0 mm in advance. It has been. Similarly, when the receiving device 14b is connected to the image forming apparatus 1, the lower limit of the movable range is set to 2.0 mm, and the oscillation width of the tray 2b is set to 2.0 mm. ing.

The oscillation width of the tray 2a is set to 2.0 mm when the receiving device 14 is not connected to the image forming apparatus 1, but is set to 0.0 mm when the receiving device 14 is connected. It is not done. This is due to the following reason.
FIG. 8 is an explanatory diagram for explaining the reason, and shows a measurement result obtained by measuring the side edge of the paper P taken out from the tray 2 by the transport unit 3 and transported by the CIS sensor 7. In this figure, the horizontal axis indicates the position of the side edge at coordinates perpendicular to the transport direction of the paper P, and the vertical axis indicates the frequency at which the paper P is measured at that position. FIG. 8A shows the measurement result when the paper P is taken out from the tray 2a, and FIG. 8B shows the measurement result when the paper P is taken out from the tray 2b or the tray 2c. Thus, when the paper P is taken out from the tray 2a, the variation of the position measured by the CIS sensor 7 is large, and the range of the variation reaches 8.0 mm. On the other hand, when the paper P is taken out from the tray 2b or the tray 2c, the range of variation in the measurement position is as small as 2.4 mm. This is because when the paper P is taken out from the tray 2a, the structure and the mounting accuracy of the tray 2a are factors, and the paper position tends not to be constant, whereas the paper P is taken out from the trays 2b and 2c. This means that the position of the paper is almost constant.

Because of this premise, even if the average value of the paper P side end position is set to the reference position of each tray 2 in the image forming pre-processing operation, in the case of the tray 2a, it is moved to this reference position. There is a case where it is necessary to move 4.0 mm. In this case, if the oscillation width is set to 2.0 mm (that is, ± 1.0 mm), the registration roll 6 may have to move the paper P by a maximum of 5.0 mm. For example, since the reference position of the tray 2a is 5.5 mm as shown in FIG. 3A, the paper taken out from the tray 2a is considered in consideration of the variation in FIG. The position of P varies in the range of 1.5 mm to 9.5 mm. Here, if the conveyed paper P is at a position of 1.5 mm and the paper position is set to 6.5 mm by the timing of oscillation, the registration roll 6 is “6.5-1.5 = 5. “0 mm” must be moved. Since the registration roll 6 moves the leading edge of the paper P in a state where the trailing edge of the paper P is held by the non-releasable paper holder as described above, the paper P is twisted when the movement amount is large, and the influence on the paper P is affected. Will become bigger. On the other hand, in the case of the tray 2b or the tray 2c, the width of variation is only 2.4 mm. For example, taking the tray 2b as an example, since the reference position of the tray 2b is 3.39 mm as shown in FIG. 3A, the paper P taken out from the tray 2b is 2.19 mm to 4.3 mm. It is conveyed in the range of 59 mm. Since the oscillation width of the tray 2b is 4.0 mm, the possible range of the paper position by the oscillation is 3.39 ± 2.0 mm, that is, 1.39 to 5.39 mm. Here, even if the conveyed paper P is at a position of 2.19 mm and the paper position is set to 5.39 mm by the timing of oscillation, the registration roll 6 is “5.39-2.19 = 3”. .2 mm ".
As described above, when the variation in the position where the sheet is conveyed is large, the correction amount to be corrected to the reference position becomes large, and thus the oscillation width cannot be increased.

  Further, the reference position is a position obtained by averaging a finite number of measurement values in the image forming pre-processing operation, and is only a sample average. Therefore, the reference position is away from the true average value of the sheet P side edge position taken out from the tray 2. There is a possibility. In particular, when the variation is large as in the tray 2a, there is a high possibility that the reference position specified in the image forming pre-processing operation and the true average value are separated from each other. In such a case, when the receiving device 14 is connected and the movable range of the paper P is narrowed, the limit of the reference position and the movable range is close, so that the oscillation width cannot be increased. .

  As described above, when the oscillation range is determined according to the combination of the receiving device 14 and the tray 2, the control unit 12 divides the oscillation range for each sheet position interval read from the storage unit 13, etc. A sheet position group discretely arranged at intervals is calculated, and a moving order in which the sheet position group moves is determined by a predetermined algorithm.

(B-4) Image Forming Operation Next, the image forming operation will be described. FIG. 9 is a flowchart for explaining the flow of the image forming operation. FIG. 10A is a diagram showing the order of movement of the paper positions in the oscillation range determined by the operation of determining the oscillation range. First, the control unit 12 reads “cumulative count”, which is a parameter obtained by cumulatively adding how many times the paper P has been conveyed for each tray 2 from the reference position table 131 of the storage unit 13 (step SA301), and according to the cumulative count. The paper position is updated (step SA302). Specifically, as shown in FIG. 10A, the control unit 12 assigns 0, 1, 2,... And a number corresponding to the movement order to the calculated sheet position. Then, the control unit 12 divides the cumulative number by the number-of-times threshold stored in the storage unit 13 as the parameter group 132, and selects the paper position of the number corresponding to the quotient. For example, in the case of the tray 2a in FIG. 3A, the cumulative number is 50 and the number threshold is 100, so the quotient is 0. Accordingly, in this case, the reference position “5.5 mm” of the tray 2a is selected as the paper position. Since this reference position does not change until the quotient changes from 0 to 1, the sheet position becomes this reference position until the cumulative number reaches 100. In the case of the tray 2b, since the cumulative number is 150, the quotient is 1. Accordingly, in this case, the sheet position is “2.89”, which is a sheet position moved by one from the reference position “3.39” of the tray 2b to the lower limit side. In this way, when the recording material is moved to a certain paper position for the number of times indicated by the frequency threshold, the paper position is updated and the recording material is moved to the next paper position.

  Next, the control unit 12 forms a toner image at a position corresponding to the paper position on the photoreceptor of the image forming unit 4 (step SA303), and takes out the paper P from the tray 2 determined in step SA102 to the transport unit 3. Then, the CIS sensor 7 is caused to measure the position in the direction perpendicular to the transport direction of the transported paper P (step SA304). Then, the control unit 12 calculates a correction amount from the difference between the measurement position and the paper position (step SA305), drives the registration roll 6 based on the correction amount, and moves the paper P (step SA306). For example, when the paper position is “5.5 mm” and the measurement position is “4.5 mm”, the correction amount is “+1.0 mm”. Therefore, in this case, the registration roll 6 sandwiches the paper P and moves it by “1.0 mm” in the plus direction on the coordinate axis x from the origin O shown in FIG. As a result, the position of the left end of the paper P moves so as to approach the paper position.

  Thereafter, the intermediate belt 9 copies the toner image formed and held on the photosensitive member of the image forming unit 4 so as to overlap the surface of the intermediate belt 9, and is conveyed to the recording position by the conveying unit 3. P is recorded (step SA307). Then, the control unit 12 increases the “cumulative number” by 1 (step SA308), and then determines whether there is a remaining job (step SA309). If it is determined that there is a remaining job (step SA309; YES), the control unit 12 returns the process to step SA302. On the other hand, if it is determined that there is no remaining job (step SA309; NO), the control unit 12 writes the “cumulative number” in the reference position table 131 of the storage unit 13 (step SA310), and this process is called as a caller. return.

  The recording material taken out from the tray 2 has a specific misalignment in a direction perpendicular to the conveying direction when conveyed to the recording position due to mechanical accuracy at the connection portion between the tray 2 and the conveying unit 3. The positional deviation is almost a numerical value for each tray 2. In the image forming apparatus 1 described above, the average of the positions measured a plurality of times for the tray 2 is used as the reference position of the tray 2, and the oscillation is performed in a range including the reference position. The deviation may increase, but the average deviation is reduced. Further, if a symmetric oscillation range centered on the reference position described above is set, the oscillation range may exceed the range in which the recording material can be moved by the registration roll 6. Even in such a case, in the image forming apparatus 1 described above, the oscillation range is set so as not to exceed the movable range while keeping the oscillation width constant. As a result, damage to the fixing device and the transfer device is suppressed.

(C) Modified Example The above-described embodiment may be modified as follows. Moreover, you may combine suitably the aspect deform | transformed as follows and the above-mentioned embodiment.
(C-1) In the above-described embodiment, the start condition for the reference position calculation process is not particularly mentioned, but various start conditions may be provided. For example, the above-described reference position calculation process may be performed when an instruction to perform the reference position calculation process is received from a user by an operation unit (not shown). Further, the tray 2 that is the storage means for the paper P needs to calculate the reference position when the parts are replaced or newly added. Therefore, a detection unit that detects that the tray 2 is mounted may be provided, and the above-described reference position calculation process may be automatically performed every time the detection unit detects that the tray 2 is mounted. In this case, for example, the image forming apparatus 1 includes a button-like switch urged by an elastic body as an example of a detection unit that detects that the tray 2 is mounted at the mounting position. In the state where the tray 2 is not mounted, since the internal contact is separated by the biasing force of the elastic body, this switch is not sent to the control unit 12 and the tray 2 is mounted. Since the internal contact contacts the urging force, a predetermined signal is sent to the control unit 12. And the control part 12 should just perform the process of the reference position calculation mentioned above whenever it receives the signal by this switch.

(C-2) In the above-described embodiment, paying attention to the fact that the position of the paper P is different for each tray 2 that is the storage means for the paper P, the reference position of the paper P is stored for each tray 2. The position of the paper P is corrected according to the difference between the reference position and the measurement position. Here, the reason why the position of the sheet P is different for each tray 2 that is a storage means for the sheet P is that the position of the sheet is different due to an attachment error of the tray 2 in the state of being stored in each tray 2. And at least one of the change of the sheet position during conveyance from the tray 2 to the recording position.

Here, the “paper transport path” includes the tray 2 that is a paper storage means, and is an area through which the paper passes from the tray 2 to the recording position. In any case, the position of the paper P is different for each paper transport path. When an embodiment is grasped from such a viewpoint, it can be expressed as follows.
That is, in the present embodiment, a moving means for moving the recording material in a direction perpendicular to the conveying direction upstream of the recording position in which the image is recorded on the recording material, and the movement Determining means for determining the presence or absence of receiving means for receiving a recording material on which an image is recorded at the recording position after being moved by the means, and a reference position serving as a reference when the moving means moves the recording material A reference position specifying means for specifying, a width storing means for storing a movement width when the recording material is moved by the moving means in association with the presence or absence of the receiving means, and the receiving determined by the determining means Each time the moving width corresponding to the presence or absence of the means is read from the width storage means and the condition for moving the recording material is satisfied, the moving hand is within the moving width with reference to the reference position. And a movement control means for moving the recording material and a plurality of conveying paths, and the recording material is moved to a recording position where an image is recorded on the recording material via any of the plurality of conveying paths. A transport unit that transports the recording unit, and the reference position specifying unit stores the reference position defined for each transport path in association with each of the storage units, and the recording transported by the transport unit. The recording material moving apparatus includes: a specifying unit that specifies a reference position stored in the storage unit in association with a material conveyance path. However, an example of the conveyance unit of the recording material moving apparatus is the conveyance unit 3 of the above embodiment, an example of the storage unit is the storage unit 13 of the above embodiment, and an example of the measurement unit is the CIS sensor 7 of the above embodiment. An example of the moving means is the registration roll 6 of the above embodiment.

(C-3) In particular, the “front-side printing” conveyance path and the “back-side printing” conveyance path in double-sided printing may be distinguished as paper conveyance paths. In double-sided printing, the recording material is transported to the reversing mechanism, then reversed and transported to the recording position again. Therefore, the transport path depends on whether the image is recorded on the front surface or the back surface of the recording material. The transport distance is also different. Therefore, because of the difference in the transport path and transport distance, the recording position often differs. In this case, for example, the storage unit 13 stores two reference positions for each tray 2. That is, the storage unit 13 uses the average measured position when the transport unit 3 transports one side of the paper P as the recording surface as a first reference position, and then the paper P is reversed by a switchback mechanism or the like. The average of the positions measured when the transport unit 3 transports the other surface as the recording surface is stored as the second reference position. When the transport unit 3 transports one side of the paper P as the recording surface, the first reference position is set, and after the paper P is reversed by a switchback mechanism or the like, the transport unit 3 sets the other side as the recording surface. In this case, the second reference position is read from the storage unit 13 as the reference position, and position correction is performed.

(C-4) In the above-described embodiment, the registration roll 6 is positioned upstream of the CIS sensor 7 in the paper conveyance direction. However, as indicated by a broken line in FIG. It may be located on the upstream side in the paper conveyance direction.

(C-5) In the above-described embodiment, the registration roll 6 corrects the difference between the paper position and the position measured by the CIS sensor 7 in order to move the left end position of the paper P closer to the paper position. However, it is not necessary to move the paper P using the difference itself as a correction amount. In short, the registration roll 6 may perform correction processing of a correction amount according to this difference. For example, the registration roll 6 may perform the correction process using a value obtained by multiplying the difference by a predetermined magnification (such as 0.8) as a correction amount.

(C-6) In the above-described embodiment, the control unit 12 assigns 0, 1, 2,... And a number corresponding to the movement order to the calculated sheet position, and divides the cumulative number by the number threshold. The paper position of the number corresponding to is selected, but the paper position may be selected by other methods. For example, in the above-described embodiment, the sheet position is sequentially selected so as to reciprocate the oscillation width as shown in FIG. 10A, and returns to the original position every 16 times. Therefore, a number from 0 to 15 is assigned over the 16 cycles, and a number corresponding to the remainder obtained by further dividing the above quotient by 16 may be selected as the paper position.
Individual numbers may be assigned to all the paper positions. For example, when the oscillation width is 4.0 mm and the paper position interval is 0.5 mm, the paper position score is “9”. As shown in FIG. 10B, if 0 to 8 is assigned to each paper position and the number corresponding to the remainder obtained by dividing the above quotient by “9” as the paper position score is selected as the paper position. The paper positions are sequentially selected in a sawtooth shape as shown in FIG. Further, when numbers 0 to 8 are alternately assigned from the center to the left and right as shown in FIG. 10C, the paper positions are sequentially selected from left and right alternately as shown in FIG. 10C.

(C-7) In the above-described embodiment, the paper position group that is discretely arranged at equal intervals over the oscillation width is calculated. However, if the paper positions are within the oscillation range, they are discrete at equal intervals. It may not be arranged. For example, the paper position group may be calculated so that the ratio of the adjacent intervals between the paper positions is constant. If the paper position is within the oscillation range, the interval between the paper positions may not be determined. For example, when the paper position is updated, the control unit 12 may generate a pseudo random number and set a position corresponding to the pseudo random number in the oscillation range as the next paper position.

(C-8) In the above-described embodiment, the control unit 12 cumulatively adds the number of conveyances that is the number of times the sheet has been conveyed for each tray 2 to the “cumulative number” of the reference position table 131 of the storage unit 13. However, other values may be cumulatively added. For example, the control unit 12 may cumulatively add a numerical value corresponding to the length in the transport direction of the paper transported for each tray 2 to the “cumulative number”. Specifically, when the A4 sheet is transported once in any tray 2, the control unit 12 adds “1” to the “cumulative number” of the tray 2, and the A2 2 in the transport direction. When the A3 paper having double length is conveyed once, “2” may be added to the “cumulative number”. In addition, instead of “cumulative count”, “cumulative distance” that is a total value of lengths of recording materials conveyed from the tray 2 in the conveyance direction may be used as such a parameter. Specifically, “210 mm” may be cumulatively added to the “cumulative distance” if the paper conveyed from the tray 2 is A4, and “420 mm” if the paper is A3.

(C-9) In the above-described embodiment, the parameter group 132 stored in the storage unit 13 includes the upper and lower limits of the movable range determined in advance for each type of the receiving device 14 being connected, and being connected. Although a predetermined oscillation width is included for each combination of the receiving device 14 and the tray 2 to be used, these parameters may be settable by the user. In this case, when the user gives an instruction for setting these parameters via an operation unit (not shown), the control unit 12 interprets this instruction and rewrites the corresponding parameter of the parameter group 132. You can do it.

(C-10) In the above-described embodiment, the connection detection unit 5 detects that any receiving device 14 is connected, and outputs identification information indicating the receiving device 14 to the control unit 12. However, the configuration of the determination unit that determines the presence / absence of the reception unit that receives the recording material or identifies the reception unit determined to be present is not limited to this. For example, an operation unit (not shown) may receive an operation from the user, and the control unit may function as a determination unit that identifies the reception unit based on the received content.
Further, the connection detection unit 5 may have a memory, and when any receiving device 14 is connected, the identification information of the receiving device 14 may be stored in this memory. In this case, the control unit 12 periodically requests the connection detection unit 5 for identification information based on a built-in timer, and outputs the identification information stored in the memory by the connection detection unit 5 when requested. It may be.
Further, instead of the identification information of the receiving device 14, range information indicating a range in which the receiving device 14 can accept the recording material may be exchanged. In this case, the control unit 12 calculates an oscillation range centered on the reference position based on the reference position and the oscillation width of the tray 2 read from the parameter group 132 of the storage unit 13, and the oscillation range is the above range. When the range indicated by the information is exceeded, the oscillation width may be appropriately modified. In addition, the storage unit 13 stores, as the parameter group 132, an alternative value different from the oscillation width, and uses the alternative value as the oscillation width when the oscillation width is corrected. Also good.

(C-11) In the above-described embodiment, the storage unit 13 stores, as the parameter group 132, an oscillation width predetermined for each combination of the receiving device 14 being connected and the tray 2 to be used. The control unit 12 determines the oscillation width according to the combination of the receiving device 14 and the tray 2. Alternatively, the oscillation width may be determined in accordance with only the type of the receiving device 14 being connected without considering which tray 2 is storing the paper. In this case, the storage unit 13 stores the oscillation width in association with the type of the receiving device 14 being connected. Moreover, regardless of the type of the receiving device 14 that is connected, only two oscillation widths may be described: the case where the receiving device 14 is connected and the case where the receiving device 14 is not connected. Further, the oscillation width may be described for each combination of the receiving device 14 being connected and the conveyance path of the paper P. Here, as described in the modification (C-2), the “paper transport path” includes the tray 2 that is a paper storage unit and the paper passes from the tray 2 to the recording position. It is an area to do.

1 is an explanatory diagram illustrating a schematic configuration example of an image forming apparatus. 3 is an explanatory diagram illustrating a functional configuration example of an image forming apparatus. FIG. It is a figure which shows an example of the reference | standard position table and parameter group of a memory | storage part. It is explanatory drawing which shows the structural example of the vicinity of a CIS sensor and a registration roll. It is a flowchart for demonstrating the flow of operation | movement of a reference position calculation. It is a flowchart for demonstrating the flow of operation | movement of an image formation pre-processing. It is a conceptual diagram for demonstrating an oscillation range. It is the measurement result which measured the side edge of the paper taken out from the tray by the conveyance part and conveyed. It is a flowchart for demonstrating the flow of operation | movement of image formation. It is a conceptual diagram for demonstrating the selection method of the paper position discretely arrange | positioned in an oscillation range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 12 ... Control part, 13 ... Memory | storage part, 131 ... Reference position table, 132 ... Parameter group, 14, 14a, 14b ... Reception apparatus, 2, 2a, 2b, 2c ... Tray, 3 ... Conveyance part DESCRIPTION OF SYMBOLS 4 ... Image formation part, 5 ... Connection detection part, 6 ... Registration roll, 7 ... CIS sensor, 7a ... Light receiving element, 8 ... Image reading part, 9 ... Intermediate belt, P ... Paper.

Claims (9)

A moving means for moving the recording material in a direction parallel to the recording surface and perpendicular to the conveying direction on the upstream side in the conveying direction of the recording material from the recording position at which an image is recorded on the recording material;
A determination unit that determines presence or absence of a receiving unit that receives a recording material on which an image is recorded at the recording position after being moved by the moving unit;
A reference position specifying means for specifying a reference position as a reference when the moving means moves the recording material;
A width storage means for storing a moving width when the recording material is moved by the moving means in association with the presence or absence of the receiving means;
The movement width corresponding to the presence / absence of the receiving means determined by the determination means is read from the width storage means, and whenever the condition for moving the recording material is satisfied, the reference position is used as a reference within the range of the movement width. And a movement control means for moving the recording material by a movement means. The width storage means stores the movement width in association with each receiving means,
The determination means identifies the receiving means determined to be present,
The movement control means reads the movement width corresponding to the receiving means identified by the determination means from the width storage means, and each time the condition for moving the recording material is satisfied, the movement control means The recording material moving apparatus according to claim 1, wherein the recording material is moved by the moving means within a range. A plurality of storage means for storing the recording material;
A transport unit that takes out the recording material from any of the plurality of storage units and transports the recording material to the recording position;
The reference position specifying means includes
Storage means for storing the reference position determined for each storage means in association with each storage means;
Specifying means for specifying a reference position stored in association with the storage means in which the recording material transported by the transport means is stored;
The width storage means stores the movement width in association with a set of the receiving means and the storage means,
The movement control means reads from the width storage means a movement width corresponding to a set of the receiving means identified by the determination means and the storage means in which the recording material conveyed by the conveyance means is stored, and the recording material 3. The recording material moving apparatus according to claim 2, wherein the recording material is moved by the moving means within a moving range of the predetermined width centered on the reference position each time a condition for moving the recording material is satisfied. Comprising measuring means for measuring a position in a direction parallel to the recording surface of the recording material conveyed by the conveying means and perpendicular to the conveying direction;
The reference position is measured by the measuring unit with respect to the plurality of recording materials, with the conveying unit taking out a plurality of the recording materials from the storage unit while the recording unit is prohibited from moving by the moving unit. The recording material moving device according to claim 3, wherein the recording material moving device is calculated from each position. Comprising a detecting means for detecting that the storage means is mounted at a mounting position of the storage means;
When the detection means detects that the storage means has been mounted, a plurality of recording materials are taken out from the storage means by the transport means in a state in which movement of the recording material by the moving means is prohibited, 5. The reference position calculated from each position measured by the measurement means for a plurality of recording materials is written and stored in the storage means as a reference position corresponding to the storage means. Recording material moving device. The storage means reverses the recording material and conveys the other surface as the recording surface, as the reference position, the first reference position when the conveying device conveys one surface of the recording material as the recording surface. The second reference position in the case is stored in association with the storage means,
The specifying means includes a first reference position when the conveying means conveys the one surface of the recording material as a recording surface, and a second reference position when the conveying surface conveys the other surface as a recording surface. The recording material moving device according to any one of claims 3 to 5, wherein each of the recording materials is specified as a reference position corresponding to a storage unit in which the recording material is stored. A plurality of conveyance paths, and a conveyance unit that conveys the recording material to a recording position where an image is recorded on the recording material via any of the plurality of conveyance paths;
The reference position specifying means includes
Storage means for storing the reference position determined for each of the transport paths in association with each of the transport paths;
The recording material movement according to claim 1, further comprising a specifying unit that specifies a reference position stored in the storage unit in association with a transport path of the recording material transported by the transport unit. apparatus. The recording material moving device according to any one of claims 1 to 7,
An image forming apparatus comprising: an image forming unit that forms an image at a position corresponding to the reference position. The image forming unit includes:
An image carrier for holding an image;
Image writing means for writing an image at a position corresponding to the reference position of the image carrier;
The image forming apparatus according to claim 8, further comprising: a transfer unit that transfers and records the image on the recording material.

Images