JP2011227353A - Image forming device and image adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of completing image adjustment processing even if a recording medium is stopped during execution of the image adjustment processing.SOLUTION: When at least one recording medium is stopped in the middle of conveyance thereof, it is determined whether or not reading of output density information on a patch image on the final recording medium existing on the most upstream side in a conveying direction of a predetermined conveying path out of the at least one recording medium is completed. Then, when it is determined that the reading of the output density information on the patch image on the final recording medium has not been completed, it is determined whether a conveying region capable of conveying the final recording medium exists or not until reading the output density information on the final recording medium is completed, and when it is determined that the conveying region capable of conveying the final recording medium exists, the final recording medium is conveyed by utilizing the conveying region.

Description

  The present invention relates to an image forming apparatus and an image adjustment method.

In recent years, image forming apparatuses such as color printers and color copiers that employ an electrophotographic system, an inkjet system, and the like have been required to improve the output image quality. In particular, the density gradation and the stability of the output image have a great influence on the user's image evaluation.
In addition, the image forming apparatus may change the density of the output image due to changes in each part of the apparatus due to changes in the installation environment or long-term use, and the color balance may be lost.

  Therefore, in order to always maintain a constant density-gradation characteristic in the output image, the output density information for each color of the patch image formed with the toner images of Y, M, C, and K colors on the transfer material, Image adjustment processing that controls the density or chromaticity of an image formed on a transfer material by reading using a sensor and comparing the read output density information with a color matching table or the like that is held in advance is known. It has been.

  By the way, patch images are often formed on a plurality of transfer sheets. However, in order to perform the above-described image adjustment processing, it is necessary to form patch images under the same image forming conditions. Therefore, when an error such as a jam occurs during the execution of the image adjustment process, it is necessary to start the image adjustment process again from the beginning, and the recording material such as paper, ink, and toner is wasted. .

  Therefore, if a predetermined error occurs during the image adjustment process that divides and forms a patch image on a plurality of transfer materials, the transfer material is immediately stopped and the patch image is read before the error occurs. A technique is disclosed in which the image adjustment process is resumed without forming the same patch image and reading the output density information for the finished transfer material (see, for example, Patent Document 1). Thereby, it is possible to prevent wasteful consumption of the recording material.

JP 2005-13049 A

  However, in the technique described in Patent Document 1, if an error occurs during image adjustment processing, for example, the final transfer paper among a plurality of transfer papers on which patch images are formed can pass through the color sensor. Even in other words, even if the output density information of the patch image can be read from the final transfer sheet, the process of stopping the transfer sheet is performed. For this reason, the transfer paper that cannot pass through the color sensor even though the patch image has already been formed is still wasted.

  In addition, it is necessary to form the patch image under the same image forming conditions, but the output density information of the patch image formed on the final transfer sheet is read out of the plurality of transfer sheets on which the patch image is formed. Even when an error occurs during the process, it is necessary to read the output density information of the patch image from the first transfer sheet again, and there is a problem that the usability is poor.

  An object of the present invention is to provide an image forming apparatus and an image adjustment method capable of completing the image adjustment process even if the recording medium is stopped during the conveyance during the image adjustment process.

  The invention described in claim 1 is made in order to achieve the above object. In the image forming apparatus, at least one transport driving unit that transports a recording medium in a transport direction along a predetermined transport path. An image forming unit that forms a patch image on a recording medium; and output density information of the patch image that is provided downstream of the image forming unit in the conveyance direction of the recording medium and formed by the image forming unit. An image reading unit that reads from each of the recording media, an image adjustment unit that adjusts image forming conditions by the image forming unit based on output density information of the patch image read by the image reading unit, and the at least one recording A control unit that controls conveyance of the medium by the conveyance driving unit, and the control unit reduces the amount of the medium when the at least one recording medium is stopped during conveyance. Reading that determines whether or not reading of output density information of a patch image on the final recording medium existing on the most upstream side in the conveying direction of the predetermined conveying path among the one recording medium is completed by the image reading unit. When the determination unit and the reading determination unit determine that the reading of the output density information of the patch image on the final recording medium by the image reading unit is not completed, the patch image output on the final recording medium is output. A conveyance area determination unit that determines whether or not there is a conveyance area in which the final recording medium can be conveyed until density information is read by the image reading unit, and the final recording medium is determined by the conveyance area determination unit. When it is determined that there is a transportable transport area, the transport drive unit transports the final recording medium using the transport area.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the transport area determination unit is a first distance from the stop position of the final recording medium to the image reading unit in the predetermined transport path. And a second distance calculation unit that calculates a second distance at which the final recording medium can be transported downstream from the stop position of the final recording medium in the predetermined transport path. Then, the first distance calculated by the first distance calculation unit and the second distance calculated by the second distance calculation unit are compared and determined, and the second distance is determined to be equal to or greater than the first distance. In this case, it is determined that there is a transport area in which the final recording medium can be transported.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the final recording medium that is provided upstream of the image reading unit in the conveyance direction of the recording medium and is conveyed by the conveyance driving unit. The recording medium detecting unit further detects the recording medium detecting unit, and the first distance calculating unit is based on a time from when the final recording medium is detected by the recording medium detecting unit to when the conveyance of the final recording medium is stopped. The first distance is calculated.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the image forming apparatus further includes a jam detection unit that detects the occurrence of a jam in the recording medium, and the second distance calculation unit includes the transport driving unit. Based on the interval between adjacent recording media between the recording medium in which the jam detected by the jam detection unit and the final recording medium among the at least one recording medium conveyed by The distance is calculated.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the transport area determination unit is transported by the transport driving unit downstream of the image reading unit. The recording medium further includes a conveyance path determination unit that determines whether a conveyance path different from the predetermined conveyance path exists as the conveyance path of the recording medium, and the conveyance path determination unit defines the predetermined conveyance path. When it is determined that a different transport path exists, it is determined whether there is a transport area in which the final recording medium can be transported.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the second to fourth aspects, the transport area determination unit determines that the second distance is shorter than the first distance. In this case, it is determined whether or not there is a transport path different from the predetermined transport path as a transport path of the recording medium transported by the transport driving unit on the downstream side of the image reading unit. And the conveyance path of the recording medium downstream from the final recording medium is the predetermined conveyance path when the conveyance path determination unit determines that there is a conveyance path different from the predetermined conveyance path. A third distance that is secured based on switching to a different conveyance path and calculating a third distance that can convey the final recording medium downstream from the stop position of the final recording medium in the predetermined conveyance path. A calculation unit; When the first distance calculated by the first distance calculation unit and the first distance calculated by the third distance calculation unit are compared and determined, and the third distance is determined to be greater than or equal to the first distance And determining that there is a transport area in which the final recording medium can be transported.

  According to a seventh aspect of the present invention, there is provided a transport driving unit that transports a recording medium in a transport direction along a predetermined transport path, an image forming unit that forms a patch image on at least one recording medium, and the image forming unit. An image reading unit that is provided downstream of the recording medium in the conveyance direction and reads output density information of a patch image formed by the image forming unit from each of the at least one recording medium, and is read by the image reading unit. An image adjustment method using an image forming apparatus comprising: an image adjusting unit that adjusts an image forming condition by the image forming unit based on output density information of a patch image, wherein the at least one recording medium is conveyed When stopping halfway, before the output density information of the patch image on the final recording medium on the most upstream side of the predetermined conveying path in the at least one recording medium. When it is determined that reading by the image reading unit is completed and reading of output density information of the patch image on the final recording medium by the image reading unit is not completed, A process for determining whether or not there is a transport area in which the final recording medium can be transported until the output density information of the patch image on the final recording medium is read by the image reading unit, and transport capable of transporting the final recording medium And a process of transporting the final recording medium by the transport drive unit using the transport area when it is determined that the area exists.

  According to the present invention, even if the recording medium is stopped during the conveyance of the image adjustment process, the final recording medium is applied to the output density of the patch image using the conveyance area downstream from the stop position of the final recording medium. The information can be conveyed until it is read, whereby the image adjustment process can be completed.

1 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to the present embodiment. 2 is a functional block diagram of the image forming apparatus 1 according to the present embodiment. FIG. FIG. 4 is a diagram illustrating an example of a transfer sheet P on which a patch image is formed by an image forming unit 110. 5 is a flowchart illustrating an example of a conveyance control process performed in the image forming apparatus 1 according to the present embodiment. It is the flowchart shown about an example of the process which calculates the distance which can be conveyed. It is a figure explaining one specific example of a mode that the process which calculates the distance which can be conveyed is performed. 10 is a flowchart illustrating an example of a conveyance control process performed in the image forming apparatus 1 according to Modification 1. It is the figure explaining one specific example of the state after switching of a conveyance route was performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to the present embodiment. FIG. 2 is a functional block diagram of the image forming apparatus 1.
As illustrated in FIGS. 1 and 2, the image forming apparatus 1 is, for example, a digital multi-function peripheral, and includes a printer unit 100 and a post-processing unit 200.

The printer unit 100 applies Y (yellow), M (for the image data (for example, image data read from a document or image data received from an external device) to a transfer sheet (recording medium) that is fed. Magenta), C (cyan), and K (black) toner images are formed, fixed, and output to the post-processing unit 200.
Specifically, the printer unit 100 includes an image forming unit 110, a patch image generation unit 120, an image adjustment unit 130, a printer control unit 140, a paper feed unit 150, and the like.

The image forming unit 110 includes a photosensitive drum as an image carrier, a charging unit that charges the photosensitive drum, an exposure unit that exposes and scans the surface of the photosensitive drum based on image data, and a development that develops the electrostatic latent image on the photosensitive drum. A transfer unit that transfers a toner image formed on the photosensitive drum to a transfer sheet as a recording medium, a cleaning unit that removes residual toner on the photosensitive drum, a fixing unit that fixes the toner image formed on the transfer sheet, and the like And forms an image on a transfer sheet based on various image data.
Further, the image forming unit 110 forms a predetermined patch image (see FIG. 3) on the transfer paper based on the patch image data by the image adjustment processing by the image adjustment unit 130.

The patch image generation unit 120 generates patch image data used for forming a patch image by the image forming unit 110. Then, the patch image generation unit 120 outputs the generated patch image data to the image forming unit 110 in accordance with an instruction from the printer control unit 140.
As described above, the patch image generation unit 120 generates patch image data used for image adjustment processing by the image adjustment unit 130.

Here, an example of the transfer paper P on which the patch image is formed is shown in FIG.
As shown in FIG. 3, the patch image is generally formed using a plurality of transfer sheets P,. On each transfer paper P, patch images of each color formed by toner images of four colors Y, M, C, and K are output side by side in a direction substantially orthogonal to the transport direction. These Y, M, C, and K patch images are formed so that the gradation (output density information) changes stepwise along the transport direction. Note that the arrows in the figure indicate the conveyance direction of the transfer paper P.

The image adjusting unit 130 adjusts image forming conditions by the image forming unit 110.
That is, the image adjusting unit 130 adjusts the image forming conditions by the image forming unit 110 so that the image (output image) formed by the image forming unit 110 always maintains a constant density-gradation characteristic. Specifically, the image adjustment unit 130 acquires the output density information of each color Y, M, C, and K of the patch image of at least one transfer paper read by the image reading unit 220 described later, and outputs the output density information. Based on the density information, image forming conditions such as the density and chromaticity of the image formed by the image forming unit 110 are adjusted.
As described above, in order to complete the image adjustment process using the patch image, the image adjustment unit 130 needs to acquire output density information of each color of the patch image formed on all the transfer sheets. .

  The printer control unit 140 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and is specified from a system program and various application programs stored in the ROM. The program is read out and expanded in the RAM, and various processes are executed in cooperation with the program expanded in the RAM to centrally control each unit of the printer unit 100.

The paper feed unit 150 includes a plurality of paper feed trays that store transfer paper, and feeds predetermined transfer paper stored in these paper feed trays to the image forming unit 110.
Each paper feed tray can accommodate transfer papers having different paper types, colors and sizes, such as plain paper, back paper, recycled paper, and high-quality paper.

In this embodiment, an example in which an electrophotographic method using transfer paper as a recording medium is applied will be described. However, the type of the recording medium and the image forming method are not limited to this, and an inkjet method, a thermal sublimation method, and the like. Other printing methods may be applied.
In addition to the above-described components, the printer unit 100 may include a scanner unit that reads image data from a document, an I / F unit that receives image data from an external device, and the like.

The post-processing unit 200 includes a post-processing unit control unit 210, an image reading unit 220, a conveyance driving unit 230, a transfer paper detection unit 240, a jam detection unit 250, a conveyance path switching unit 260, and the like.
The post-processing unit 200 is provided with a conveyance path R for conveying the transfer paper supplied from the printer unit 100 in a predetermined direction. The transport path R is composed of, for example, various rollers, belts, guides, and the like. Then, the transfer paper conveyed from the upstream side (the printer unit 100 side) to the downstream side along the conveyance path R is discharged from a paper discharge unit T provided on the downstream side of the conveyance path R.

The post-processing unit control unit 210 includes, for example, a CPU, a RAM, a ROM, and the like. The post-processing unit control unit 210 reads a specified program from the system programs and various application programs stored in the ROM, expands the program in the RAM, and the RAM. Various processes are executed in cooperation with the program developed in Specifically, the post-processing unit control unit 210 controls the reading control unit 211 that controls the image reading unit 220, the conveyance driving unit 230, the transfer paper detection unit 240, the jam detection unit 250, and the conveyance path switching unit 260. A conveyance control unit 212.
Further, the post-processing unit control unit 210 (the reading control unit 211 and the conveyance control unit 212) and the printer control unit 140 are connected to each other via a predetermined communication network N so that data communication can be performed.

The image reading unit 220 is disposed downstream of the image forming unit 110 in the transport direction so as to face the image forming surface of the transfer paper transported along the transport path R. Further, the image reading unit 220 is driven under the control of the reading control unit 211 of the post-processing unit control unit 210, and, for example, reflects reflected light that is irradiated from a light source and reflected on the image forming surface of the transfer paper by a CCD (Charge). The output density information of each color of the patch image formed on the transfer paper is acquired by reading with an image sensor such as a coupled device.
The output density information of the patch image acquired by the image reading unit 220 is output to the image adjustment unit 130 via the post-processing unit control unit 210 and the printer control unit 140.

  Here, in the image adjustment processing by the image adjustment unit 130, as described above, it is necessary to acquire output density information of each color of the patch image formed on all the transfer sheets. Therefore, the image reading unit 220 needs to read the output density information of each color of the patch image formed on all the transfer sheets conveyed along the conveyance path R.

The conveyance drive unit 230 includes a plurality of conveyance rollers 231 to 237 and a plurality of drive sources (not shown) such as a drive motor that rotates each of the conveyance rollers 231 to 237 in a predetermined direction. Yes.
Each of the plurality of transport rollers 231 to 237 is disposed at a predetermined position in the main body of the post-processing unit 200. Among these, the first transport roller 231 to the sixth transport roller 236 are transported along the transport path R. It arrange | positions at predetermined intervals from the direction upstream to the downstream. The transport driving unit 230 is driven under the control of the transport control unit 212 of the post-processing unit control unit 210, and the first transport roller 231 to the sixth transport roller 236 are driven at a predetermined rotational speed in a predetermined direction by a drive source. Rotate with As a result, the transport driving unit 230 transports the transfer sheet on which the image is formed by the printer unit 100 along the transport path R at a substantially constant predetermined transport speed (for example, a linear speed V).
Here, when a plurality of transfer sheets are continuously conveyed, for example, the continuous transfer sheets are separated from each other by a predetermined time interval so that the driving force of the plurality of transfer rollers is not transmitted to the one transfer sheet. Transport. As a result, a plurality of transfer sheets on which patch images are formed are not completely conveyed, and the transfer sheets are stopped in the middle of the conveyance path. Occurs.

The seventh transport roller 237 constitutes an alternative transport route that is different from the reference transport route (transport path R) configured by the first transport roller 231 to the sixth transport roller 236 and the like.
In other words, when the transfer route is switched by a transfer path switching unit 260 described later, along an alternative transfer route different from the reference transfer route (transfer path R) configured by the first transfer roller 231 to the sixth transfer roller 236. The transfer paper is then conveyed. In this alternative conveyance route, the transfer paper sent downstream via the fourth conveyance roller 234 is conveyed to the seventh conveyance roller 237 side instead of the fifth conveyance roller 235, and downstream via the seventh conveyance roller 237. To the sixth transport roller 236.
In the present embodiment, the transfer paper is transported along a reference transport route (transport path R) configured by the first transport roller 231 to the sixth transport roller 236 and the like, and the seventh transport roller 237 is transported. The conveyance along the alternative conveyance route using the method will be described later in a modification of the image forming apparatus 1.

  Further, the transfer sheet conveyed along the reference conveyance route (conveyance path R) or the alternative conveyance route can be located at any position along the conveyance route, so that the first conveyance roller 231 to the seventh conveyance are present. The driving force of any one of the rollers 237 can be transmitted. In other words, even if the transfer paper on which the patch images are formed is not completed and the transfer paper is stopped in the middle of the transfer route, a jam occurs and the transfer paper other than the transfer paper that cannot move is transferred. With respect to the transfer paper, the driving force of any one of the first transport roller 231 to the seventh transport roller 237 can be transmitted to move in the transport direction.

The transfer paper detection unit 240 includes a plurality of position detection sensors 241 to 245 that detect transfer paper (recording medium) conveyed along a predetermined conveyance route (a reference conveyance route or an alternative conveyance route) in the main body of the post-processing unit 200. It has.
The plurality of position detection sensors 241 to 245 are optical sensors, for example, and transfer paper depending on whether the light is irradiated from the light source and blocked by the transfer paper conveyed along the conveyance route. The position of the front end (the downstream end in the transport direction) and the rear end (the upstream end in the transport direction) is detected.
Among the plurality of position detection sensors 241 to 245, the first position detection sensor 241 to the fourth position detection sensor 244 have a predetermined interval from the upstream side in the transport direction to the downstream side along the transport path R (reference transport route). It is arranged in the space. Specifically, the first position detection sensor 241 is arranged upstream of the image reading unit 220, while the second position detection sensor 242 to the fourth position detection sensor 244 are downstream of the image reading unit 220. Is arranged.
The fifth position detection sensor 245 is arranged on the alternative conveyance route, and detects the transfer paper conveyed along the alternative conveyance route.

The transfer paper detection unit 240 detects the passage timing of the transfer paper conveyed along the predetermined conveyance route by the conveyance driving unit 230 based on the position detection signals of the plurality of position detection sensors 241 to 245. . The transfer paper detection unit 240 outputs the detected passage timing information to the conveyance control unit 212 of the post-processing unit control unit 210.
The passage timing information is used in a conveyance control process and the like described later (described later).

  The jam detection unit 250 detects the occurrence of a jam (paper jam) in the transfer paper transport process by the transport driving unit 230. Then, the jam detection unit 250 outputs the detected jam occurrence information to the transport control unit 212 of the post-processing unit control unit 210.

The conveyance path switching unit 260 is disposed near a branch point with the alternative conveyance route in the conveyance path R (reference conveyance route), and conveys the transfer sheet in accordance with an instruction from the conveyance control unit 212 of the post-processing unit control unit 210. Switch routes.
That is, the transport path switching unit 260 is provided between the fourth transport roller 234 and the fifth transport roller 235, and before the transport route is switched (that is, the normal transport transport route), The transfer paper fed downstream via the roller 234 is guided to the fifth transport roller 235 side. On the other hand, when the transport route is switched from the reference transport route to the alternative transport route, the transfer paper sent downstream via the fourth transport roller 234 is transferred to the seventh transport roller 237 side (alternative instead of the fifth transport roller 235 side). Guide to the transport route side).
The alternative conveyance route and the reference conveyance route merge at the downstream side of the fifth conveyance roller 235 (seventh conveyance roller 237), and the transfer paper conveyed through the alternative conveyance route is the reference conveyance route (fifth conveyance roller). In the same manner as the transfer paper conveyed through the roller), it is fed to the sixth conveying roller 236 side.

  In addition to the above-described components, the post-processing unit 200 includes a sorting unit that performs sorting of sheets on which images are formed, a punch unit that performs punching processing, and a stapling process that binds a bundle of sheets at a set binding position. A stapling unit that performs the folding process, a folding unit that performs the folding process, a cutting unit that performs the cutting process, and the like may be provided.

  As described above, the image forming apparatus 1 according to the present embodiment includes a conveyance driving unit 230 that conveys a recording medium (transfer paper) in a conveyance direction along a predetermined conveyance path R, and patch images on a plurality of recording media. An image forming unit 110 to be formed, an image reading unit 220 provided on the downstream side of the image forming unit 110 and reading output density information of a patch image formed by the image forming unit 110 from each of a plurality of recording media, and an image Based on the output density information of the patch image read by the reading unit 220, an image adjustment unit 130 that adjusts image forming conditions by the image forming unit 110 and a conveyance control that controls conveyance of a plurality of recording media by the conveyance driving unit 230. Unit 212.

Next, the operation of the image forming apparatus 1 according to the present embodiment will be described.
FIG. 4 is a flowchart illustrating an example of a conveyance control process performed in the image forming apparatus 1. This conveyance control process is a program in which the CPU of the post-processing unit control unit 210 (reading control unit 211, conveyance control unit 212) is stored in the ROM when the occurrence of a jam is detected by the jam detection unit 250. It is realized by executing.

  As shown in FIG. 4, in step S <b> 11, it is determined whether reading of output density information of the final patch image by the image reading unit 220 is completed. The final patch image is a patch image formed on the last transfer paper among a plurality of transfer papers on which the patch image is formed. If it is determined that the reading of the output density information of the final patch image has been completed (step S11: YES), the transfer control process is terminated because there is no need to transfer the transfer sheet any more. On the other hand, if it is determined that the reading of the output density information of the final patch image has not been completed (step S11: NO), the process proceeds to step S12.

In step S12, a distance required for completion of image adjustment is calculated. Specifically, the distance required to complete the image adjustment is the distance until the reading of the output density information of the final patch image is completed, that is, the final transfer paper on which the final patch image is formed passes through the image reading unit 220. It is the distance to do. The distance S necessary for completion of image adjustment is calculated using a calculation formula shown in the following formula (1).
S = (D + L) −T × V (1)
Note that D in Expression (1) is a distance from the image reading unit 220 to the first position detection sensor 241 of the transfer paper detection unit 240 that detects the final transfer paper on which the final patch image is formed. L is the length of the transfer paper in the transport direction, T is the time from when the transfer paper detector 240 detects the final transfer paper to the time when the transfer paper stops, V is This is the linear speed of the transfer paper.

  As described above, the image forming apparatus 1 performs image processing based on the time from when the final transfer paper on which the final patch image is formed is detected by the transfer paper detection unit 240 to when the final transfer paper is stopped. A distance (first distance) necessary for completion of the adjustment is calculated.

  In step S13, a process for calculating a transportable distance is performed. The process for calculating the transportable distance will be described in detail with reference to the flowchart of FIG. Hereinafter, the transfer paper is expressed as Pn, the transfer paper on which the jam has occurred is expressed as P0, and P1, P2,. The final transfer paper on which the final patch image is formed is denoted as Pfin.

  As shown in FIG. 5, in calculating the distance that can be transported in this process, in step S131, the distance between adjacent transfer sheets in the transport direction is sequentially added starting from the transfer sheet P0 where the jam has occurred. Therefore, n = 0 is set, and 0 is set as the transportable distance.

  In step S132, 1 is added to n (n = n + 1). As a result, the target transfer paper Pn moves to the transfer paper Pn + 1 that is transported one after.

In step S133, it is determined whether or not the transfer paper Pn can be sent (conveyed) to the downstream side by the driving force of the conveyance roller (for example, the sixth conveyance roller 236) of the conveyance driving unit 230 in which the jam has occurred. To do. In other words, at the moment when a jam occurs, all the transport rollers 231 to 237 of the transport drive unit 230 are urgently stopped, but the transfer paper P1 transported immediately behind the transfer paper P0 where the jam has occurred is If the distance between the transfer paper P0 and the transfer paper P0 is small, the transfer paper P0 may enter a driving force transmission range (transportable range) by a transport roller (for example, the sixth transport roller 236) where the paper jam occurs. There is.
Therefore, in step S133, when it is determined that the sheet can be sent downstream by the driving force of the conveyance roller in which the jam has occurred (step S133: YES), the process proceeds to step S132, and the target is conveyed one after. The transfer paper Pn + 1 is moved. On the other hand, when it is determined that the sheet cannot be sent to the downstream side due to the driving force of the transport roller in which the jam has occurred (step S133: NO), the process proceeds to step S134.

  In step S134, the length between the transfer paper Pn and the transfer paper Pn-1 transported immediately before is added to the transportable distance.

  In step S135, 1 is added to n (n = n + 1). As a result, the target transfer paper Pn moves to the transfer paper Pn + 1 that is transported one after.

  In step S136, it is determined whether or not the transfer sheet Pn is the final transfer sheet Pfin on which the final patch image is formed, that is, whether or not Pn = Pfin. When Pn = Pfin (step S136: YES), the process proceeds to step S137. On the other hand, if Pn ≠ Pfin (step S136: NO), the process proceeds to step S134, and the target is moved to the transfer paper Pn + 1 to be conveyed one after.

  In step S137, the length between the final transfer paper Pfin and the transfer paper Pfin-1 transported immediately before is added to the transportable distance. As a result, the sheet interval between the transfer sheets from the transfer sheet P0 where the jam has occurred to the final transfer sheet Pfin is summed, so that the distance that the final transfer sheet Pfin can be conveyed can be calculated.

  As described above, the image forming apparatus 1 can convey the distance between the adjacent transfer sheets between the transfer sheet P0 where the jam has occurred and the final transfer sheet Pfin on which the final patch image is formed (the first distance that can be conveyed). 2 distance) is calculated.

  Here, with reference to FIG. 6, an example of a state in which a process for calculating a concrete transportable distance is performed will be described. In the drawing, X represents a jam occurrence point, and P0 to P5 represent transfer sheets. The transfer paper P3 is the final transfer paper (Pfin).

As shown in FIG. 6, since the transfer paper P0 is jammed at the point X, the transfer paper detection unit 240 (c in FIG. 6) that has passed immediately before the position of the transfer paper P1 that is transported one time later. Is calculated based on the passage timing information detected by the. In FIG. 6, the transfer paper P1 cannot be sent to the downstream side by the driving force of the sixth transport roller 236 of the transport drive unit 230 in which a jam has occurred, so that the paper is between the transfer paper P0 and the transfer paper P1. It can be seen that there is a gap.
The length between the sheets is set at equal intervals in advance, but can be calculated based on, for example, position information of both transfer sheets. The length between sheets is added to the transportable distance. Next, the position of the transfer paper P2 is calculated, and it is determined whether or not this transfer paper P2 is the final transfer paper Pfin (P3 in FIG. 6). In FIG. 6, since the transfer sheet P2 is not the final transfer sheet Pfin, the length between the sheets P1 and P2 is added to the transportable distance.
Thereafter, the above process is repeated until the position of the final transfer paper Pfin on which the final patch image is formed is calculated. When the position of the final transfer paper Pfin is calculated, the length between the final transfer paper Pfin and the previous transfer paper Pfin-1 (P2 in FIG. 6) is added to the transportable distance. To do. As a result, the distance between the transfer sheets from the transfer sheet P0 where the jam has occurred to the final transfer sheet Pfin is added up, and therefore the distance that the final transfer sheet Pfin can be conveyed can be calculated.

  Next, in step S14 of FIG. 4, the distance necessary for completion of image adjustment calculated in step S12 is compared with the transportable distance calculated in step S13, and the distance that can transport the final transfer paper is determined as the image. It is determined whether or not the distance is necessary for completion of adjustment. If it is determined that the distance capable of transporting the final transfer paper is equal to or longer than the distance necessary for completion of image adjustment (step S14: YES), the process proceeds to step S15. On the other hand, when it is determined that the transportable distance is less than the distance necessary for completion of image adjustment (step S14: NO), reading of the output density information of the final patch image cannot be completed. And the process starts again after reading the first patch image.

In step S15, each transfer sheet is conveyed until the final transfer sheet Pfin on which the final patch image is formed passes through the sensor area of the image reading unit 220. Specifically, for example, among the transfer sheets other than the transfer sheet in which a jam has occurred, among the transfer sheets that can be sent to the downstream side in the transport direction, the operation of sequentially feeding the transfer sheet from the most downstream side to the downstream side is performed. . That is, the most downstream transfer paper P1 is sent to the downstream side by the distance between the transfer paper P0 and the transfer paper P0 which is one downstream of the transfer paper by driving the third transport roller 233. Then, the transfer paper P2 that is one upstream from the most downstream transfer paper is transferred between the transfer paper P1 and the transfer paper P1 that is one downstream from the transfer paper by driving the second conveying roller 232. The sheet P1 and the transfer sheet P0 are sent to the downstream side by the distance between the sheets. This operation is repeated until the final transfer paper Pfin on which the final patch image is formed passes through the sensor area of the image reading unit 220.
In this way, by using the transportable area generated by moving the transfer paper downstream of the final transfer paper to the downstream side, it is possible to pass through the sensor area of the image reading unit 220 of the final transfer paper. The feeding operation, that is, the reading of the output density information of the final patch image can be completed.

As described above, the conveyance control unit 212 exists on the most upstream side of the predetermined conveyance path R among the plurality of transfer sheets when conveyance of the plurality of transfer sheets is stopped in the middle of the predetermined conveyance path R. It functions as a reading determination unit that determines whether or not the reading of the output density information of the patch image (final patch image) on the final transfer sheet by the image reading unit 220 has been completed.
The conveyance control unit 212 also outputs the output density information of the final patch image to the image reading unit 220 when the reading determination unit determines that the reading of the output density information of the final patch image by the image reading unit 220 has not been completed. It functions as a transport area determination unit that determines whether there is a transport area in which the final transfer paper can be transported until it is read.
When the transport area determination unit determines that there is a transport area in which the final transfer paper can be transported, the transport control unit 212 causes the transport driving unit 230 to transport the final transfer paper using the transport area.

Further, the conveyance area determination unit of the conveyance control unit 212 functions as a first distance calculation unit that calculates a first distance from the stop position of the final transfer sheet on the predetermined conveyance path R to the image reading unit 220.
The conveyance area determination unit of the conveyance control unit 212 functions as a second distance calculation unit that calculates a second distance at which the final transfer paper can be conveyed downstream from the stop position of the final transfer paper in the predetermined conveyance path R. To do.
Then, the conveyance control unit 212 compares and determines the first distance calculated by the first distance calculation unit and the second distance calculated by the second distance calculation unit, and the second distance is equal to or greater than the first distance. If it is determined, it is determined that there is a transport area in which the final transfer paper can be transported.

Accordingly, even when a jam occurs on the downstream side of the conveyance path R and the conveyance of the transfer sheet is stopped (jam occurrence point X; see FIG. 6), the conveyance of the downstream side from the stop position of the final transfer sheet is performed. A sufficient area can be secured (that is, the distance that the final transfer paper on which the final patch image is formed can be conveyed), and the output density information of the patch image is read from the final transfer paper using the conveyance area. The image adjustment process (reading the output density information of the final patch image) can be completed.
In addition, wasteful consumption of the recording material can be prevented, and it is not necessary to perform the image adjustment process again, so that the cost and time can be reduced.

<Modification 1>
FIG. 7 is a flowchart illustrating an example of a conveyance control process performed in the image forming apparatus 1 according to the first modification. Note that Modification 1 differs from the above embodiment in that the transportable distance is ensured by switching the transport path when it is determined that the transportable distance is less than the distance necessary for completion of image adjustment. .

  As shown in FIG. 7, steps S21 to S23 are the same as steps S11 to S13 in the transport control process shown in FIG.

In step S24, the distance necessary for completion of the image adjustment calculated in step S22 is compared with the transportable distance calculated in step S23, and whether the transportable distance is equal to or greater than the distance necessary for completion of image adjustment. Determine whether. When it is determined that the transportable distance is greater than or equal to the distance necessary for completion of image adjustment (step S24: YES), the process proceeds to step S25.
In step S25, each transfer sheet is conveyed until the final transfer sheet Pfin on which the final patch image is formed passes through the sensor area of the image reading unit 220, as in step S15 in the above embodiment. Thereby, reading of the output density information of the final patch image can be completed.

On the other hand, when it is determined in step S24 that the transportable distance is less than the distance necessary for completion of image adjustment (step S24: NO), the process proceeds to step S26.
In step S26, it is determined whether or not there is a switchable transport path (alternative transport route). If it is determined that there is a switchable transport path (step S26: YES), the process proceeds to step S27. On the other hand, if it is determined that there is no switchable transport path (step S26: NO), the reading of the output density information of the final patch image cannot be completed, so that the transport control process is terminated and the first The process starts from reading the patch image.

  In step S27, the conveyance path is switched by controlling the conveyance path switching unit 260. When the switching of the transport path is completed, the process proceeds to step S23, and a process of calculating a transportable distance is performed again to determine whether transfer paper can be transported.

  Here, an example of a state after the conveyance path is specifically switched will be described with reference to FIG. In FIG. 8, after the conveyance path switching unit 260 is controlled and the conveyance path is switched from the state of FIG. 6, the final transfer paper P3 on which the final patch image is formed passes through the sensor area of the image reading unit 220. FIG. 6 is a diagram illustrating a state in which transfer sheets P2 and P3 are conveyed.

  As illustrated in FIG. 8, the image forming apparatus 1 according to the first modification controls the conveyance path switching unit 260 when it is determined in the conveyance control process that the conveyable distance is less than the distance necessary for completion of image adjustment. Then, the conveyance path is switched. FIG. 8 shows a state where the transport path is switched from the transport path R to the alternative transport route. When the transport path R is switched to the alternative transport route, a new transportable distance is calculated, and it is determined whether or not the calculated distance is greater than or equal to a distance necessary for completion of image adjustment (for convenience of explanation). In this case, it is assumed that the distance is longer than that necessary for completion of image adjustment). The newly transportable distance is, for example, the transport distance until the most downstream transfer paper (P2 in FIG. 8) of the transfer paper existing upstream of the transport path switching unit 260 reaches the end of the alternative transport route. It is calculated by calculating. If it is determined that the distance is longer than necessary for completion of image adjustment, transfer paper (P2 and P3 in FIG. 8) existing between the transport path switching unit 260 and the final transfer paper Pfin is transported. Specifically, the fourth transport roller 234 is rotated to transport the transfer paper P2 on the most downstream side of the transfer paper existing upstream from the transport path switching unit 260, and the transfer paper P3 on the one upstream side is rotated. In order to carry, the 3rd conveyance roller 233 is rotated. This operation is repeated until the final transfer paper Pfin on which the final patch image is formed passes through the sensor area of the image reading unit 220. Thus, the transfer paper feeding operation, that is, the reading of the output density information of the final patch image, can be completed until the final transfer paper Pfin on which the final patch image is formed passes through the sensor area of the image reading unit 220.

As described above, when it is determined that the second distance is shorter than the first distance, the conveyance control unit (conveyance region determination unit) 212 is conveyed by the conveyance driving unit 230 downstream from the image reading unit 220. It functions as a transport path determination unit that determines whether there is a transport path different from the predetermined transport path R as the transfer path of the transfer paper.
In addition, the conveyance control unit (conveyance area determination unit) 212, when the conveyance path determination unit determines that there is a conveyance path different from the predetermined conveyance path R, the transfer sheet on the downstream side in the conveyance direction from the final transfer sheet. The final transfer paper can be transported downstream from the stop position of the final transfer paper in the predetermined transport path R, which is secured based on switching the transport path to a transport path different from the predetermined transport path R. It functions as a third distance calculation unit that calculates the third distance.
The conveyance control unit (conveyance region determination unit) 212 compares and determines the first distance calculated by the first distance calculation unit and the first distance calculated by the third distance calculation unit, and the third distance is the first distance. If it is determined as above, it is determined that there is a transport area in which the final transfer paper can be transported.

  Thus, for example, the transfer paper that is downstream of the final transfer paper is further transported downstream by means of switching to a transport path different from the predetermined transport path R, such as the transport path switching unit 260 shown in FIG. Can be secured for a longer time, and as a result, a transport area capable of transporting the final transfer paper is secured, and image adjustment processing (reading of output density information of the final patch image) is completed. it can.

  As mentioned above, although concretely demonstrated based on embodiment which concerns on this invention, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.

For example, in the above modification, a configuration including two transport paths is illustrated, but this is not a limitation. If it is possible to provide more transport paths, it is possible to secure a longer transportable distance, and the effect of the present invention can be made more effective.
In the above modification, the transportable distance is calculated again after switching the transport path. However, the transportable distance after the transport path switching is calculated first, and the calculated distance is the image adjustment. When it is determined that the distance is greater than or equal to the distance necessary for completion, the conveyance path may be switched.
In the above modification, when it is determined that there is a transport path different from the predetermined transport path, the third distance is calculated to determine whether there is a transport area in which the final recording medium can be transported. However, when it is determined that there is a transport path different from the predetermined transport path, it may be determined that there is a transport area in which the final recording medium can be transported automatically.

  In the above-described embodiment, the jam is illustrated as an example in which the transfer paper is stopped in the middle of the predetermined transport path R. However, an error related to transport other than the jam (for example, a failure of the apparatus or the like). ) Is provided, it is possible to apply the present invention to a conveyance error other than a jam.

  In the above embodiment, the image adjustment is completed based on the time from when the final transfer paper on which the final patch image is formed is detected by the transfer paper detection unit 240 to when the conveyance of the final transfer paper is stopped. Although the necessary distance (first distance) is calculated, the present invention is not limited to this, and any calculation method may be used as long as the distance necessary for completion of image adjustment can be calculated.

  In the above embodiment, the transportable distance (second distance) is calculated based on the interval between adjacent transfer sheets between the transfer sheet P0 where the jam has occurred and the final transfer sheet Pfin. However, the present invention is not limited to this, and any calculation method may be used as long as the transportable distance can be calculated.

  In the above embodiment, the case where the patch image is formed by using a plurality of transfer sheets is described as an example. However, the present invention can also be applied to a case where the patch image is one sheet. It is. In this case, the image forming unit 110 forms a patch image on at least one recording medium.

  In addition, the detailed configuration and detailed operation of each apparatus constituting the image forming apparatus 1 can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 100 Printer part 110 Image forming part 120 Patch image generation part 130 Image adjustment part 140 Printer control part 150 Paper feed unit 200 Post-processing part 210 Post-processing part control part 211 Reading control part 212 Conveyance control part 220 Image reading part 230 Conveyance Drive Unit 240 Transfer Paper Detection Unit 250 Jam Detection Unit 260 Conveyance Path Switching Unit

Claims (7)

A transport driving unit configured to transport the recording medium in a transport direction along a predetermined transport path;
An image forming unit that forms a patch image on at least one recording medium;
An image reading unit provided downstream of the image forming unit in the conveyance direction of the recording medium and reading output density information of a patch image formed by the image forming unit from each of the at least one recording medium;
An image adjusting unit that adjusts image forming conditions by the image forming unit based on output density information of the patch image read by the image reading unit;
A control unit that controls conveyance of the at least one recording medium by the conveyance driving unit,
The controller is
When the at least one recording medium is stopped in the middle of conveyance, the output density information of the patch image on the final recording medium existing most upstream in the conveyance direction of the predetermined conveyance path among the at least one recording medium. A reading determination unit that determines whether reading by the image reading unit is completed;
When the reading determination unit determines that the reading of the output density information of the patch image on the final recording medium by the image reading unit is not completed, the output density information of the patch image on the final recording medium is A transport region determination unit that determines whether or not there is a transport region in which the final recording medium can be transported until it is read by the image reading unit;
When the transport region determination unit determines that there is a transport region in which the final recording medium can be transported, the final recording medium is transported by the transport driving unit using the transport region. Forming equipment. The conveyance area determination unit
A first distance calculation unit that calculates a first distance from a stop position of the final recording medium in the predetermined conveyance path to the image reading unit;
A second distance calculating unit that calculates a second distance at which the final recording medium can be transported downstream from a stop position of the final recording medium in the predetermined transport path;
When the first distance calculated by the first distance calculation unit is compared with the second distance calculated by the second distance calculation unit, and it is determined that the second distance is equal to or greater than the first distance. 2. The image forming apparatus according to claim 1, wherein it is determined that there is a transport area in which the final recording medium can be transported. A recording medium detection unit that is provided upstream of the image reading unit in the conveyance direction of the recording medium and detects the final recording medium conveyed by the conveyance driving unit;
The first distance calculator is
3. The first distance is calculated based on a time from when the final recording medium is detected by the recording medium detection unit to when the conveyance of the final recording medium is stopped. Image forming apparatus. A jam detecting unit for detecting occurrence of jam in the recording medium;
The second distance calculator is
Of the at least one recording medium conveyed by the conveyance driving unit, based on the interval between adjacent recording media between the recording medium in which the jam detected by the jam detecting unit has occurred and the final recording medium. The image forming apparatus according to claim 2, wherein the second distance is calculated. The conveyance area determination unit
A transport path determination unit that determines whether there is a transport path different from the predetermined transport path as a transport path of the recording medium transported by the transport driving unit downstream from the image reading unit; Have
The transport path determination unit determines whether there is a transport area in which the final recording medium can be transported when it is determined that a transport path different from the predetermined transport path exists. The image forming apparatus as described in any one of 1-4. The conveyance area determination unit
When it is determined that the second distance is shorter than the first distance, the predetermined transport path as a transport path of the recording medium transported by the transport driving unit downstream of the image reading unit. A transport path determination unit that determines whether there is a transport path different from
When the conveyance path determination unit determines that there is a conveyance path different from the predetermined conveyance path, the conveyance path of the recording medium downstream from the final recording medium is different from the predetermined conveyance path. A third distance calculating unit that calculates a third distance that can be transported downstream from the stop position of the final recording medium in the predetermined transport path, which is secured based on switching to transport to Further comprising
When the first distance calculated by the first distance calculation unit and the first distance calculated by the third distance calculation unit are compared and determined, and it is determined that the third distance is greater than or equal to the first distance 5. The image forming apparatus according to claim 2, wherein it is determined that there is a transport area in which the final recording medium can be transported. A transport driving unit configured to transport the recording medium in a transport direction along a predetermined transport path;
An image forming unit that forms a patch image on at least one recording medium;
An image reading unit provided downstream of the image forming unit in the conveyance direction of the recording medium and reading output density information of a patch image formed by the image forming unit from each of the at least one recording medium;
An image adjustment method using an image forming apparatus comprising: an image adjusting unit that adjusts image forming conditions by the image forming unit based on output density information of a patch image read by the image reading unit;
When the at least one recording medium stops in the middle of conveyance, among the at least one recording medium, the output density information of the patch image on the final recording medium located on the most upstream side in the conveyance direction of the predetermined conveyance path A process of determining whether reading by the image reading unit is completed;
When it is determined that the reading of the output density information of the patch image on the final recording medium by the image reading unit is not completed, the output density information of the patch image on the final recording medium is read by the image reading unit. A process of determining whether or not there is a transport area in which the final recording medium can be transported until
When it is determined that there is a transport area in which the final recording medium can be transported, the image adjustment is performed using the transport area to transport the final recording medium by the transport driving unit. Method.

Images