IMAGE PROCESSING APPARATUS AND IMAGE PROCESSING METHOD

An image processing apparatus includes a registration roller, a first conveying roller, and a second conveying roller. The registration roller is disposed on a conveying path of a sheet to be subjected to image processing, and corrects the skew of the sheet by allowing the leading end of the sheet abut thereon in a stopped state. The first conveying roller is disposed upstream of the registration roller on the conveying path at a position where a first loop space for deflecting the sheet is interposed between the first conveying roller and the registration roller. The second conveying roller is disposed upstream of the first conveying roller at a position where a second loop space is interposed between the two conveying rollers. The second conveying roller conveys the sheet at a conveying speed that is equal to or higher than the conveying speed of the first conveying roller.

INCORPORATION BY REFERENCE

This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2022-129869 filed on Aug. 17, 2022, the entire contents of which are incorporated herein by reference.

The present disclosure relates to an image processing apparatus and an image processing method.

BACKGROUND

As related art, there is known an image processing apparatus (image forming system) provided with a sheet conveying device that drives a registration roller after having the leading end of a sheet (paper) abut on a nip portion of the registration roller in a stopped state and correcting the skew of the sheet (aper skew correction). In the image processing apparatus according to the related art, a loop roller for deflecting a sheet is disposed upstream of the registration roller, and when the skew of the sheet is corrected, whether or not to stop the driving of the loop roller or whether or not to decelerate the driving of the loop roller is controlled depending on the type of the sheet.

SUMMARY

An image processing apparatus according to one aspect of the present disclosure includes a registration roller, a first conveying roller, and a second conveying roller. The registration roller is disposed on a conveying path of a sheet to be subjected to image processing, and corrects the skew of the sheet by allowing the leading end of the sheet to abut thereon in a stopped state. The first conveying roller is disposed upstream of the registration roller on the conveying path at a position where a first loop space for deflecting the sheet is interposed between the first conveying roller and the registration roller. The first conveying roller conveys the sheet at a first conveying speed. The second conveying roller is disposed upstream of the first conveying roller on the conveying path at a position where a second loop space for deflecting the sheet is interposed between the second conveying roller and the first conveying roller. The second conveying roller conveys the sheet at a second conveying speed that is equal to or higher than the first conveying speed.

An image processing method according to another aspect of the present disclosure includes: driving a registration roller disposed on a conveying path of a sheet to be subjected to image processing and configured to correct a skew of the sheet by allowing a leading end of the sheet to abut thereon in a stopped state; driving a first conveying roller disposed upstream of the registration roller on the conveying path at a position where a first loop space for deflecting the sheet between the first conveying roller and the registration roller and configured to convey the sheet at a first conveying speed; and driving a second conveying roller disposed upstream of the first conveying roller on the conveying path at a position where a second loop space for deflecting the sheet is interposed between the second conveying roller and the first conveying roller and configured to convey the sheet at a second conveying speed that is equal to or higher than the first conveying speed.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below with reference to the accompanying drawings. The following embodiments are examples of embodying the present invention and do not limit the technical scope of the present invention.

First Embodiment

[1] Overall Configuration of Image Processing Apparatus

First, an overall configuration of an image processing apparatus10according to the present embodiment will be described with reference toFIG.1andFIG.2.

The image processing apparatus10according to the present embodiment is, for example, a multifunction peripheral having a plurality of functions such as a scanning function for obtaining image data from a document sheet, a printing function for forming an image based on the image data, a facsimile function, and a copy function. The image processing apparatus10may be a printer, a scanner, a facsimile machine, a copier, or the like as long as it has an image processing function including at least one of the function of forming an image and the function of obtaining image data.

As shown inFIG.2, the image processing apparatus10is roughly composed of a main body1(main body unit) and an extension device2(enhancement unit). The main body1has an image processing function (at least one of the function of forming an image and the function of obtaining image data). The “extension device” in the present disclosure is an optional device detachably connected to the main body1, and is an enhancement that adds various extended functions to the image processing apparatus. The main body1and the extension device2are used in a state of being electrically and mechanically connected.

That is, while having the functions of the main body1as basic functions, the image processing apparatus10can implement various extended functions desired by the user by combining the main body1with desired extension devices2. In other words, the image processing apparatus10includes the main body1having the image processing function, and an extension device2is detachably connected to the main body1. Specific examples of the extension device2include devices such as a stapling machine, a folding machine, an inserter, a booklet folder, and a mail folder. These extension devices2are “post-processing devices” that perform post-processing, such as stapling, on sheets on which images have been formed in the main body1.

In the present embodiment, as an example, the image processing apparatus10includes a finisher (post-processing device) having a function as a stapling machine as the extension device2, and further includes any extension device2selected from a folding machine, an inserter, a booklet folder, a mail folder, and the like. That is, the image processing apparatus10can connect one or more extension devices2to one main body1.

As shown inFIG.1, the main body1includes a first conveying portion11, an image reading portion12, an image forming portion13, a sheet feed portion14, an operation display portion15, and a control portion16. In the present embodiment, as shown inFIG.2, the main body1includes a housing101. The first conveying portion11, the image reading portion12, the image forming portion13, the sheet feed portion14, the operation display portion15, and the control portion16are provided in the housing101.

The first conveying portion11conveys a sheet Sh1(seeFIG.3) to be subjected to image formation or image reading along a first conveying path L1(seeFIG.3). As will be described in detail later, the first conveying portion11sequentially conveys sheets Sh1to be subjected to image processing (image formation or image reading) with one or more roller pairs disposed on the first conveying path L1formed in the main body1. Here, although the sheet Sh1conveyed by the first conveying portion11is paper as an example, it is not limited to paper, and may be, for example, a resin film.

The image reading portion12reads an image from a document sheet (sheet Sh1) and outputs image data corresponding to the read image. The image reading portion12includes a document sheet table, a light source, a plurality of mirrors, an optical lens, a charge coupled device (CCD), and the like.

The image forming portion13forms an image on the sheet Sh1using an electrophotographic method, based on the image data output from the image reading portion12. In addition, the image forming portion13forms an image on the sheet Sh1based on image data input from an information processing apparatus, such as a personal computer, external to the image processing apparatus10. The image forming portion13includes four image forming units corresponding to four colors of C (cyan), M (magenta), Y (yellow), and K (black), a laser scanning unit, an intermediate transfer belt, a secondary transfer roller, a fixing device, and the like. The image forming portion13may form an image on the sheet Sh1using an image forming method other than the electrophotographic method, such as an inkjet method.

The image forming portion13forms an image on the sheet Sh1using toner as a developer. When the image forming portion13forms an image using an inkjet method, ink (another example of the developer) is supplied instead of the toner. Examples of the toner supplied to the image forming portion13include toners of a plurality of colors of C (cyan), M (magenta), Y (yellow), and K (black). The sheet Sh1on which an image has been formed by the image forming portion13is conveyed by the first conveying portion11to the extension device2as a post-processing device for post-processing.

The sheet feed portion14supplies the sheet Sh1to the image forming portion13. The sheet feed portion14includes a sheet feed cassette, a manual feed tray, a sheet conveying path, and a plurality of conveying rollers. The image forming portion13forms an image on the sheet Sh1supplied from the sheet feed portion14.

The operation display portion15is a user interface in the image processing apparatus10. The operation display portion15includes a display portion, such as a liquid crystal display, for displaying various types of information in response to a control instruction from a control portion of the main body, and an operation portion, such as a switch or a touch panel, for inputting various types of information to the control portion of the main body in response to a user's operation. In addition, the image processing apparatus10may include, as a user interface, an audio output portion, an audio input portion, and the like, in addition to or instead of the operation display portion15.

The control portion16comprehensively controls the image processing apparatus10. In the present embodiment, the control portion16controls at least the first conveying portion11of the main body1and a second conveying portion22of the extension device2. Specifically, the control portion16controls the conveying speed of the sheet Sh1in the first conveying portion11, the conveying speed of the sheet Sh1in the second conveying portion22, whether the sheet Sh1should be conveyed or not (stopped), and the like.

The control portion16is mainly composed of a computer system including one or more processors and one or more memories. In the image processing apparatus10, the functions of the control portion16are implemented by one or more processors executing programs. The programs may be stored in advance in the memories, may be provided through a telecommunications line such as the Internet, or may be provided by being stored in a non-transitory recording medium, such as an optical disk, readable by the computer system. The one or more processors are composed of one or more electronic circuits, including a semiconductor integrated circuit. Further, the computer system here includes a microcontroller having one or more processors and one or more memories. The control portion16includes a memory used as a temporary storage memory (work area) for various types of processing executed by the control portion16. The control portion16may be a control portion provided separately from the main control portion which comprehensively controls the image processing apparatus10.

In addition, the image processing apparatus1further includes a storage portion, a communication portion, and the like. The storage portion includes one or more nonvolatile memories, and stores in advance information, such as control programs, for causing the control portion16to execute various types of processing. The communication portion is an interface that executes data communication between the image processing apparatus10and an external apparatus connected via a communication network such as the Internet or a local area network (LAN).

In the present embodiment, among a plurality of extension devices2, the extension device2as a finisher is directly connected to the main body1, and the other extension devices2are indirectly connected to the main body1by being connected to the extension device2as a finisher. In other words, when the main body1is regarded as a “parent”, the extension device2as a finisher can be regarded as a “child”, and the other extension devices2can be regarded as “grandchildren”. Thus, it is possible to add any function to the finisher by combining any device such as a folding machine or an inserter as another extension device2(grandchild enhancement) with the extension device2as a finisher (child enhancement). However, the plurality of extension devices2basically employ a common configuration insofar as the configuration to be described below is concerned.

As shown inFIG.1, the extension device2includes an extended function portion21and the second conveying portion22. In the present embodiment, as shown inFIG.2, the extension device2includes a housing102. The extended function portion21and the second conveying portion22are provided in the housing102. Here, the housing102may be configured to have a plurality of extension devices2collectively provided in one housing102, or be dividable (separable) for the respective extension devices2.

The extended function portion21implements a function (post-processing) to be added to the main body1as the extension device2. That is, when the extension device2is a stapling machine, the extended function portion21executes stapling processing, and when the extension device2is a folding machine, the extended function portion21executes sheet folding processing.

The second conveying portion22conveys the sheet Sh1to be subjected to post-processing along a second conveying path L2(seeFIG.3). As will be described in detail later, the second conveying portion22sequentially conveys sheets Sh1to be subjected to post-processing with one or more roller pairs disposed on the second conveying path L2formed in the extension device2.

That is, the second conveying portion22conveys, along the second conveying path L2in the extension device2, the sheet Sh1conveyed by the first conveying portion11of the main body1and discharged from the main body1to the extension device2. Therefore, the first conveying path L1of the main body1and the second conveying path L2of the extension device2are continuous, and the sheet Sh1is conveyed from the first conveying path L1to the second conveying path L2. In other words, a conveying path L10(seeFIG.3) includes the first conveying path L1and the second conveying path L2, and the sheet Sh1is conveyed along the conveying path L10by the first conveying portion11and the second conveying portion22.

The connecting work between the main body1and the extension device2is performed by the user (including a contractor such as a service person). That is, the user electrically connects, for example, a desired extension device2to the main body1. In this way, the user performs the connecting work between the main body1and the extension device2in accordance with the configuration (combination) of the extension device2connected to the main body1.

[2] Skew Correction of Sheet

In the image processing apparatus10as described above, when the sheet Sh1conveyed by the second conveying portion22is skewed, the post-processing executed by the extension device2is performed on the sheet Sh1in the skewed state. Therefore, it is useful for the image processing apparatus10to employ means for correcting the skew of the sheet Sh1.

The image processing apparatus10according to the present embodiment employs a mechanical registration mechanism as means for correcting the skew of the sheet Sh1. The mechanical registration mechanism is a mechanism for performing skew correction for correcting the skew itself of the conveyed sheet Sh1, using a registration roller221(seeFIG.3) disposed on the conveying path L10.

Specifically, the mechanical registration mechanism corrects the skew of the sheet Sh1by causing the leading end of the sheet Sh1conveyed along the conveying path L10to collide with a nip portion of the registration roller221in a stopped state. The “leading end” of the sheet Sh1here is an edge on the leading end (front end) side of the sheet Sh1in the conveying direction, and is a part of the sheet Sh1being conveyed which first reaches (comes into contact with) the registration roller221. After adjusting the posture of the sheet Sh1(correcting the skew) in this way, the mechanical registration mechanism corrects the skew of the conveyed sheet Sh1by rotating the registration roller221.

As related art of this type of image processing apparatus10, there is known an image processing apparatus (image forming system) provided with a sheet conveying device that drives a registration roller after having the leading end of a sheet (paper) abut on a nip portion of the registration roller in a stopped state and correcting the skew of the sheet (paper skew correction). In the image processing apparatus according to the related art, a loop roller for deflecting a sheet is disposed upstream of the registration roller, and when the skew of the sheet is corrected, whether or not to stop the driving of the loop roller or whether or not to decelerate the driving of the loop roller is controlled depending on the type of the sheet.

In the configuration of the related art described above, when the basic conveying speed is high, a relatively long sheet is conveyed in a short time, and the deflection (loop) of the sheet tends to become unstable when correcting the skew of the sheet, which may cause damage to the sheet.

In contrast, in the present embodiment, when correcting the skew of the sheet Sh1, the image processing apparatus10can easily stabilize the deflection of the sheet Sh1with the configuration to be described below.

That is, as shown inFIG.3, the image processing apparatus10according to the present embodiment includes a registration roller221, a first conveying roller111, and a second conveying roller112. The registration roller221is disposed on the conveying path L10of the sheet Sh1to be subjected to image processing, and corrects the skew of the sheet Sh1by allowing the leading end of the sheet Sh1to abut thereon in the stopped state. The first conveying roller111is disposed upstream of the registration roller221on the conveying path L10at a position where a first loop space Sp1is interposed between the first conveying roller111and the registration roller221. The first loop space Sp1is a space for deflecting the sheet Sh1. The first conveying roller111conveys the sheet Sh1at a first conveying speed. The second conveying roller112is disposed upstream of the first conveying roller111on the conveying path L10at a position where a second loop space Sp2is interposed between the second conveying roller112and the first conveying roller111. The second loop space Sp2is a space for deflecting the sheet Sh1. The second conveying roller112conveys the sheet Sh1at a second conveying speed that is equal to or higher than the first conveying speed.

In short, in the present embodiment, the first conveying roller111and the second conveying roller112, which is further upstream of the first conveying roller111and conveys the sheet Sh1at a conveying speed (second conveying speed) equal to or higher than that of the first conveying roller111, are disposed upstream of the registration roller221. The registration roller221allows the leading end of the sheet Sh1to abut thereon in the stopped state, that is, in a state where the conveying speed is 0 (zero) and adjusts the posture of the sheet Sh1(corrects the skew), and then starts to rotate, thereby constituting a mechanical registration mechanism that corrects the skew of the sheet Sh1.

The term “upstream” in the present disclosure means upstream in the flow of the sheet Sh1being conveyed on the conveying path L10, and is opposite to downstream. That is, the sheet Sh1conveyed along the conveying path L10is conveyed from upstream to downstream of the conveying path L10. In addition, the term “loop” in the present disclosure refers to a loop-like deflection (slack) formed by the sheet Sh1deflecting when the conveying speed of the leading end side of the sheet Sh1is lower than the conveying speed of the trailing end side.

That is, basically, when the conveying speed of the upstream conveying roller (first conveying roller111) is equal to or higher than the conveying speed of the downstream conveying roller (registration roller221), a loop (deflection) may be generated between the first conveying roller111and the registration roller221due to the speed difference. Here, the conveying speed includes “0” as in the stopped state of the registration roller221. Similarly, when the conveying speed of the upstream conveying roller (second conveying roller112) is equal to or higher than the conveying speed of the downstream conveying roller (first conveying roller111), a loop (deflection) may be generated between the second conveying roller112and the first conveying roller111due to the speed difference.

In the present embodiment, the first conveying roller111is disposed at a position upstream of the registration roller221across the first loop space Sp1for forming a loop (deflection of the sheet Sh1) as described above. Similarly, the second conveying roller112is disposed at a position upstream of the first conveying roller111across the second loop space Sp2for forming a loop (sheet Sh1).

Accordingly, a loop (deflection of the sheet Sh1) caused by the difference in conveying speed between the registration roller221and the first conveying roller111is generated in the first loop space Sp1, and a loop (deflection of the sheet Sh1) caused by the difference in conveying speed between the first conveying roller111and the second conveying roller112is generated in the second loop space Sp2. As a result, the deflection of the sheet Sh1is distributed to two locations, and the amount of deflection of the sheet Sh1per location is reduced, thereby reducing damage to the sheet Sh1. As described above, the image processing apparatus10according to the present embodiment has an advantage that the deflection of the sheet Sh1is easily stabilized when the skew of the sheet Sh1is corrected.

In addition, the image processing apparatus10according to the present embodiment includes the main body1and the extension device2as a post-processing device. The sheet Sh1on which image processing (image formation or image reading) has been performed in the main body1is then conveyed from the main body1to the extension device2for post-processing. Therefore, in the image processing apparatus10, the conveying path L10of the sheet Sh1has a first conveying path L1formed in the main body1, which is the upstream side, and a second conveying path L2formed in the extension device2, which is the downstream side.

In other words, the image processing apparatus10includes a downstream unit and an upstream unit. Here, the downstream unit has the registration roller221, and the upstream unit has the first conveying roller111. The conveying path L10is formed to be continuous from the upstream unit to the downstream unit. In the present embodiment, as an example, the main body1is the upstream unit, and the extension device2is the downstream unit. Therefore, in the present embodiment, the registration roller221is provided in the extension device2, and the first conveying roller111is provided in the main body1. The conveying path L10is formed to be continuous from the first conveying path L1of the main body1to the second conveying path L2of the extension device2.

According to the above configuration, even if the sheet Sh1is skewed when being conveyed from the upstream unit (the main body1in the present embodiment) to the downstream unit (the extension device2in the present embodiment), this skew can be corrected between the upstream unit and the downstream unit.

[3] Detailed Configurations of Conveying Portions

Next, configurations of the conveying portions (first conveying portion11and second conveying portion22) which convey the sheet Sh1will be described in more detail with reference toFIG.3.

First, the first conveying portion11is provided in the main body1, which is the upstream unit. The first conveying portion11includes the first conveying roller111and the second conveying roller112, and conveys the sheet Sh1along the first conveying path L1. In the example ofFIG.3, the first conveying path L1extends in the left-right direction in the figure, and the first conveying portion11conveys the sheet Sh1from the right side to the left side in the figure.

The first conveying roller111is disposed at the downstream end of the first conveying path L1, that is, at a position where the first conveying path L1connects to the second conveying path L2of the downstream unit (the extension device2in the present embodiment). In the present embodiment, as an example, a pair of first conveying rollers111are provided in the width direction (up-down direction in the figure) of the conveying path L10(first conveying path L1) so as to nip the sheet Sh1conveyed through the conveying path L10(first conveying path L1). The pair of first conveying rollers111are in contact with each other with a predetermined pressure, and convey the sheet Sh1toward the downstream side of the conveying path L10(the registration roller221side) by nipping the sheet Sh1therebetween. As long as at least one of the pair of first conveying rollers111is a drive roller driven by a motor, the other may be a driven roller.

The second conveying roller112is disposed a predetermined distance upstream from the first conveying roller111on the first conveying path L1. In the present embodiment, as an example, a pair of second conveying rollers112are provided in the width direction (up-down direction in the figure) of the conveying path L10(first conveying path L1) so as to nip the sheet Sh1conveyed through the conveying path L10(first conveying path L1). The pair of second conveying rollers112are in contact with each other with a predetermined pressure, and convey the sheet Sh1toward the downstream side of the conveying path L10(the first conveying roller111side) by nipping the sheet Sh1therebetween. As long as at least one of the pair of second conveying rollers112is a drive roller driven by a motor, the other may be a driven roller.

The first conveying path L1has a width dimension (dimension in the up-down direction in the figure) slightly larger than the thickness of the sheet Sh1. Thus, the sheet Sh1conveyed along the first conveying path L1can pass through the first conveying path L1and is guided in the traveling direction by the inner surface of the first conveying path L1. A part of the first conveying path L1whose width dimension is partially enlarged functions as a second loop space Sp2.

The second loop space Sp2is disposed between the first conveying roller111and the second conveying roller112on the first conveying path L1. That is, the second loop space Sp2is located upstream when viewed from the first conveying roller111and downstream when viewed from the second conveying roller112. In the present embodiment, as an example, the second loop space Sp2has a triangular cross-sectional shape such that the width dimension (dimension in the up-down direction in the figure) increases toward the upstream side, and the width dimension gradually narrows toward the downstream side.

On the other hand, the second conveying portion22is provided in the extension device2, which is the downstream unit. The second conveying portion22includes the registration roller221and an introduction sensor222, and conveys the sheet Sh1along the second conveying path L2. In the example ofFIG.3, the second conveying path L2extends in the left-right direction in the figure, and the second conveying portion22conveys the sheet Sh1from the right side to the left side in the figure.

The registration roller221is disposed a predetermined distance downstream from the upstream end of the second conveying path L2. In the present embodiment, as an example, a pair of registration rollers221are provided in the width direction (up-down direction in the figure) of the conveying path L10(second conveying path L2) so as to nip the sheet Sh1conveyed through the conveying path L10(second conveying path L2). The pair of registration rollers221are in contact with each other with a predetermined pressure, and convey the sheet Sh1toward the downstream side of the conveying path L10by nipping the sheet Sh1therebetween. As long as at least one of the pair of registration rollers221is a drive roller driven by a motor, the other may be a driven roller.

The second conveying path L2has a width dimension (dimension in the up-down direction in the figure) slightly larger than the thickness of the sheet Sh1. Thus, the sheet Sh1conveyed along the second conveying path L2can pass through the second conveying path L2and is guided in the traveling direction by the inner surface of the second conveying path L2. A part of the second conveying path L2whose width dimension is partially enlarged functions as the first loop space Sp1.

The first loop space Sp1is disposed at the upstream end of the second conveying path L2, that is, at a position where the second conveying path L2connects to the first conveying path L1of the upstream unit (the main body1in the present embodiment). That is, the first loop space Sp1is positioned upstream when viewed from the registration roller221, and downstream when viewed from the first conveying roller111. Here, since the first loop space Sp1is located at an introduction part (introduction port) of the sheet Sh1in the second conveying path L2, the first loop space Sp1is located immediately after the first conveying roller111. In the present embodiment, as an example, the first loop space Sp1has a triangular cross-sectional shape such that the width dimension (dimension in the up-down direction in the figure) increases toward the upstream side, and the width dimension gradually narrows toward the downstream side.

The introduction sensor222is a sensor for detecting the sheet Sh1introduced into the second conveying path L2. In the present embodiment, as an example, the introduction sensor222is an optical sensor, and is disposed at a position facing the conveying path L10(second conveying path L2). Here, the introduction sensor222is disposed between the registration roller221and the first loop space Sp1on the second conveying path L2. That is, the introduction sensor222is located upstream when viewed from the registration roller221, and downstream when viewed from the first loop space Sp1.

The second conveying portion22stops the registration roller221after the leading end of the sheet Sh1conveyed to the second conveying path L2by the first conveying portion11is detected by the introduction sensor222, until a stop time required for generation of a loop (deflection of the sheet Sh1) necessary for skew correction elapses. Thus, the leading end of the sheet Sh1conveyed by the first conveying portion11abuts on the registration roller221in the stopped state, causing a loop in the sheet Sh1and executing skew correction. Thereafter, the second conveying portion22accelerates the registration roller221to a predetermined conveying speed, and conveys the sheet Sh1with the registration roller221.

[4] Sheet Conveying Operation

Next, the sheet conveying operation of the image processing apparatus10according to the present embodiment will be described in detail by comparing it with an image processing apparatus10X according to a comparative example. The image processing apparatus10X according to the comparative example differs from the image processing apparatus10according to the present embodiment in that the second loop space Sp2and the second conveying roller112are omitted from the image processing apparatus10according to the present embodiment as shown inFIG.4.

That is, the image processing apparatus10X according to the comparative example includes the registration roller221and the first conveying roller111. The registration roller221is disposed on the conveying path L10of the sheet Sh1to be subjected to image processing, and corrects the skew of the sheet Sh1by allowing the leading end of the sheet Sh1to abut thereon in the stopped state. The first conveying roller111is disposed upstream of the registration roller221on the conveying path L10at a position where the first loop space Sp1is interposed between the first conveying roller111and the registration roller221.

When the mechanical registration correction is completed in the main body1, the conveying roller upstream of the registration roller221is also stopped while the registration roller221is stopped, thereby suppressing the generation of the loop more than necessary. However, in the configuration in which the main body1and the extension device2are separated as in the comparative example, for example, there is a problem when the conveying roller (the first conveying roller111or the like) of the main body1, which is the upstream unit, is stopped while the sheet Sh1is located at the fixing device, so that the conveying roller of the main body1does not stop even while the registration roller221of the extension device2, which is the downstream unit, is stopped.

Therefore, in the image processing apparatus10X according to the comparative example, the first conveying roller111continues to convey the sheet Sh1while the second conveying portion22stops the registration roller221, until a predetermined stop time elapses after the leading end of the sheet Sh1is detected by the introduction sensor222. At this time, only a loop (deflection of the sheet Sh1) having a length necessary for skew correction is generated in the first loop space Sp1.

Thereafter, the second conveying portion22accelerates the registration roller221to a predetermined conveying speed, and conveys the sheet Sh1with the registration roller221. At this time, acceleration control is performed to increase the conveying speed (number of rotations) of the registration roller221in steps from 0 (stopped state) to a predetermined speed so as to prevent the motor that drives the registration roller221from stepping out. Therefore, during the acceleration period in which the registration roller221is accelerated, the length of the sheet Sh1conveyed from the first conveying roller111on the upstream side is longer than the length of the sheet Sh1sent out from the registration roller221. Therefore, during the acceleration period, the loop (deflection of the sheet Sh1) is extended (increased) in the first loop space Sp1by a length corresponding to the difference in length.

FIG.5is a diagram schematically showing the extension of the loop during the acceleration period of the registration roller221with respect to the image processing apparatus10X according to the comparative example. InFIG.5, the horizontal axis represents the time elapsed from the start of the acceleration period (i.e., the release of the stopped state of the registration roller221), and the vertical axis represents the conveying speed.

During the acceleration period, the conveying speed V1of the registration roller221gradually increases with time and finally reaches a predetermined speed V2. The predetermined speed V2is the same as the conveying speed of the first conveying roller111upstream of the registration roller221. As an example, when the predetermined speed V2is 600 [mm/s], as shown inFIG.5, during the acceleration period, the difference between the conveying speed V1of the registration roller221and the conveying speed (predetermined speed V2) of the first conveying roller111on the upstream side causes the loop to extend in the first loop space Sp1by a length corresponding to the difference, that is, by a length corresponding to the hatched area A1inFIG.5. Therefore, at the end of the acceleration period, a longer loop is generated in the first loop space Sp1, which consists of a loop having a length necessary for skew correction and a loop having a length corresponding to the hatched area A1.

As a result, a relatively large loop space (first loop space Sp1) is required between the registration roller221and the first conveying roller111. If the loop space is small, as shown inFIG.4, the sheet Sh1may curve significantly, which may cause damage, such as a crease, to the sheet Sh1. On the contrary, if the loop space is large, the push of the sheet Sh1into the registration roller221necessary for skew correction becomes insufficient, leading to a decrease in the accuracy of the skew correction of the sheet Sh1.

On the other hand, in the image processing apparatus10according to the present embodiment, the first conveying roller111continues to convey the sheet Sh1while the second conveying portion22stops the registration roller221, until a predetermined stop time elapses after the leading end of the sheet Sh1is detected by the introduction sensor222. In the present embodiment, at the same time when the registration roller221stops, the conveying speed (first conveying speed V11) of the first conveying roller111is reduced (decelerated) from the same speed as the conveying speed (second conveying speed V12) of the second conveying roller112. However, the first conveying roller111is not stopped, but only decelerated.

At this time, only a loop (deflection of the sheet Sh1) having a length necessary for skew correction is generated in the first loop space Sp1. Further, in the second loop space Sp2, a loop (deflection of the sheet Sh1) having a length corresponding to the difference between the reduced conveying speed (first conveying speed V11) of the first conveying roller111and the conveying speed (second conveying speed V12) of the second conveying roller112located upstream thereof is generated. In short, in the image processing apparatus10according to the present embodiment, since the second loop space Sp2is provided, a loop is generated not only in the first loop space Sp1but also in the second loop space Sp2.

Thereafter, the second conveying portion22accelerates the registration roller221to a predetermined conveying speed, and conveys the sheet Sh1with the registration roller221. At this time, acceleration control is performed to increase the conveying speed (number of rotations) of the registration roller221in steps from 0 (stopped state) to a predetermined speed so as to prevent the motor that drives the registration roller221from stepping out. Therefore, during the acceleration period in which the registration roller221is accelerated, the length of the sheet Sh1conveyed from the first conveying roller111on the upstream side is longer than the length of the sheet Sh1sent out from the registration roller221. Therefore, during the acceleration period, the loop (deflection of the sheet Sh1) is extended (increased) in the first loop space Sp1by a length corresponding to the difference in length.

Furthermore, in the present embodiment, the first conveying roller111starts accelerating at the same time as the registration roller221or with a certain amount of time difference. That is, where the first conveying speed V11of the first conveying roller111is decelerated as the registration roller221is stopped, the first conveying speed V11is accelerated as the registration roller221is accelerated. The first conveying speed V11is accelerated to the first conveying speed V11(i.e., the second conveying speed V12) before deceleration (i.e., before the registration roller221is stopped). Therefore, during the acceleration period of the registration roller221, the loop (deflection of the sheet Sh1) is extended (increased) in the second loop space Sp2by a length corresponding to the difference between the first conveying speed V11and the second conveying speed V12.

FIG.6is a diagram schematically showing the extension of the loop during the acceleration period of the registration roller221with respect to the image processing apparatus10according to the present embodiment. InFIG.6, the horizontal axis represents the time elapsed from the start of the acceleration period (i.e., the release of the stopped state of the registration roller221), and the vertical axis represents the conveying speed.

During the acceleration period, the conveying speed V1of the registration roller221gradually increases with time and finally reaches the second conveying speed V12. In addition, during the acceleration period, the first conveying speed V11of the first conveying roller111gradually increases with time and finally reaches the second conveying speed V12. In the present embodiment, acceleration of the first conveying speed V11is started when the conveying speed V1of the registration roller221reaches the first conveying speed V11. As an example, it is assumed that the second conveying speed V12is 600 [mm/s] and the first conveying speed V11after deceleration is 400 [mm/s].

In this case, as shown inFIG.6, during the acceleration period, the difference between the conveying speed V1of the registration roller221and the conveying speed (first conveying speed V11) of the first conveying roller111on the upstream side causes the loop to extend in the first loop space Sp1by a length corresponding to the difference, that is, by a length corresponding to the hatched area A11inFIG.6. In addition, during the acceleration period, the difference between the conveying speed (first conveying speed V11) of the first conveying roller111and the conveying speed (second conveying speed V12) of the second conveying roller112on the upstream side causes the loop to extend in the second loop space Sp2by a length corresponding to the difference, that is, by a length corresponding to the hatched area A12inFIG.6.

Accordingly, at the end of the acceleration period, a loop is generated in the first loop space Sp1, which consists of a loop having a length necessary for skew correction and a loop having a length corresponding to the hatched area A11. In addition, a loop is generated in the second loop space Sp2, which consists of a loop having a length corresponding to the difference between the decelerated first conveying speed V11and the second conveying speed V12and a loop having a length corresponding to the hatched area A12.

As is clear from comparison ofFIG.6withFIG.5, the image processing apparatus10according to the present embodiment can keep the extended length of the loop generated during the acceleration period shorter than in the image processing apparatus10X according to the comparative example. That is, the extended length of the loop can be shortened by the difference between the hatched area A1and the hatched areas A11and A12. Moreover, since the loop having the length corresponding to the hatched areas A11and A12is generated in a dispersed manner in the first loop space Sp1and the second loop space Sp2, the loop generated in one loop space is significantly shorter than in the comparative example.

As a result, according to the image processing apparatus10of the present embodiment, there is an advantage that the deflection of the sheet Sh1is easily stabilized when correcting the skew of the sheet Sh1.

In addition, in the present embodiment, as described above, the conveying speed of the first conveying roller111(the first conveying speed V11) is variable. That is, the first conveying roller111can change the first conveying speed V11. Accordingly, the length of the loop generated in the first loop space Sp1and the length of the loop generated in the second loop space Sp2can be appropriately adjusted using the first conveying speed V11.

Moreover, in the present embodiment, the first conveying roller111changes the first conveying speed V11in accordance with the conveying speed V1of the registration roller221. That is, the first conveying speed V11changes in synchronization with the conveying speed V1of the registration roller221. Specifically, the first conveying speed V11is decelerated as the registration roller221stops, and is accelerated as the registration roller221is accelerated. This allows the first conveying roller111to function as a buffer between the registration roller221and the second conveying roller112and effectively shorten the loop.

In particular, in the present embodiment, during the acceleration period from when the registration roller221is in the stopped state to when the registration roller221reaches the predetermined conveying speed (second conveying speed V12), the deflection length of the sheet Sh1generated in the first loop space Sp1due to the difference between the conveying speeds of the registration roller221and the first conveying roller111is larger than the deflection length of the sheet Sh1generated in the second loop space Sp2due to the difference between the first conveying speed V11and the second conveying speed V12. That is, by adjusting the first conveying speed V11during the acceleration period, the hatched area A11is made larger than the hatched area A12inFIG.6. This allows the loop in the second loop space Sp2to be kept relatively small, and allows the second loop space Sp2itself to be kept small.

Further, in the present embodiment, the second conveying roller112accelerates the second conveying speed V12after the sheet Sh1passes through the image processing portion (the image reading portion12and/or the image forming portion13) that performs image processing on the sheet Sh1. That is, the conveying speed (second conveying speed V12) of the second conveying roller112is also not constant, and can be accelerated within a range in which it does not affect the image processing portion of the main body1. This makes it possible to shorten the time required for the sheet Sh1to be discharged (to the extension device2).

An example of the procedure of an operation particularly relating to the conveyance of the sheet Sh1of the image processing method executed by the image processing apparatus10(mainly the control portion16) will be described below with reference toFIG.7. Here, steps S1, S2, . . . in the flowchart shown inFIG.7represent the numbers of the processing procedure (steps) executed by the image processing apparatus10.

In step S1, the image processing apparatus10determines whether or not the leading end of the sheet Sh1has reached the registration roller221. When the sheet Sh1discharged from the first conveying path L1of the main body1is introduced into the second conveying path L2of the extension device2, the introduction sensor222detects the leading end of the sheet Sh1. With this, the image processing apparatus10determines that the leading end of the sheet Sh1has reached the registration roller221(S1: Yes), and shifts the processing to step S2. On the other hand, when the introduction sensor222does not detect the leading end of the sheet Sh1, the image processing apparatus10determines that the leading end of the sheet Sh1has not reached the registration roller221(S1: No), and shifts the processing to step S1.

In step S2, the image processing apparatus10stops the registration roller221. In addition, in step S3, the image processing apparatus10reduces the conveying speed (first conveying speed V11) of the first conveying roller111. Thus, the leading end of the sheet Sh1conveyed by the decelerated first conveying roller111abuts on the registration roller221in the stopped state, causing a loop in the sheet Sh1to execute skew correction.

In step S4, the image processing apparatus10determines whether or not a predetermined stop time has elapsed after the stop of the registration roller221. The stop time is a time for a loop (deflection of the sheet Sh1) having a length necessary for skew correction to be generated in the first loop space Sp1. If the stop time has not elapsed (S4: No), the image processing apparatus10shifts the processing to step S4. If the stop time has elapsed (S4: Yes), the image processing apparatus10shifts the processing to step S5. In step S5, the image processing apparatus10accelerates the registration roller221. Thus, the registration roller221in the stopped state is gradually accelerated, and the sheet Sh1is conveyed by the registration roller221.

In step S6, the image processing apparatus10determines whether or not the conveying speed V1of the registration roller221accelerated from the stopped state has reached the first conveying speed V11. If the conveying speed V1of the registration roller221has not reached the first conveying speed V11(S6: No), the image processing apparatus10shifts the processing to step S5and continues the acceleration of the registration roller221. When the conveying speed V1of the registration roller221reaches the first conveying speed V11(S6: Yes), the image processing apparatus10shifts the processing to step S7. In step S7, the image processing apparatus10accelerates the first conveying roller111. Thus, the decelerated first conveying speed V11is gradually accelerated.

In step S8, the image processing apparatus10determines whether or not the first conveying speed V11of the first conveying roller111accelerated from the decelerated state has reached the second conveying speed V12. If the first conveying speed V11has not reached the second conveying speed V12(S8: No), the image processing apparatus10shifts the processing to step S7and continues the acceleration of the first conveying roller111. When the first conveying speed V11reaches the second conveying speed V12(S8: Yes), the image processing apparatus10shifts the processing to step S9. In step S9, the image processing apparatus10stops the acceleration of the registration roller221and the first conveying roller111, and fixes the conveying speed V1of the registration roller221and the first conveying speed V11.

The operation described above makes it possible to realize an image processing method that can easily stabilize the deflection of the sheet Sh1when correcting the skew of the sheet Sh1. The procedure of the image processing method described above is merely an example, and the order of the processes shown in the flowchart ofFIG.7may be changed as appropriate.

The plurality of constituent elements included in the image processing apparatus10may be distributed across a plurality of housings. For example, the control portion16may be provided separately from the first conveying portion11or the like, or may be provided in the extension device2or the like other than the main body1.

In addition, in the first embodiment, the control portion16of the main body1comprehensively controls the first conveying portion11of the main body1and the second conveying portion22of the extension device2, but the present disclosure is not limited to this configuration. For example, a control unit portion may be provided in the extension device2separately from the control portion16of the main body1, and the second conveying portion22may be controlled by this control portion.

In addition, as long as the first loop space Sp1is located between the registration roller221and the first conveying roller111, it is not necessarily provided in the second conveying path L2of the extension device2, and may be provided in the first conveying path L1of the main body1. That is, the first loop space Sp1may be located downstream of the first conveying roller111in the first conveying path L1.

In addition, the shape of each of the first loop space Sp1and the second loop space Sp2is not limited to a triangular cross-sectional shape, and various shapes such as a square cross-sectional shape or an elliptical cross-sectional shape can be adopted. Further, each of the first loop space Sp1and the second loop space Sp2may be divided into a plurality of parts. That is, for example, a plurality of first loop spaces Sp1may be arranged between the registration roller221and the first conveying roller111, and a plurality of second loop spaces Sp2may be arranged between the first conveying roller111and the second conveying roller112.

In addition, the registration roller221, the first conveying roller111, and the second conveying roller112are not limited to the configuration in which a pair of each is provided, and one or three or more of each may be provided. Further, a plurality of pairs of each of the registration roller221, the first conveying roller111, and the second conveying roller112may be provided.

Second Embodiment

An image processing apparatus10A according to the present embodiment differs from the image processing apparatus10according to the first embodiment in that it includes a relay conveying unit3as shown inFIG.8. In the following, structures similar to those of the first embodiment are denoted by common reference numerals, and descriptions thereof are omitted as appropriate.

The relay conveying unit3is located between the main body1and the extension device2, which is the post-processing device. In the image processing apparatus10A according to the present embodiment, the sheet Sh1discharged from the main body1is conveyed to the extension device2via the relay conveying unit3. That is, the relay conveying unit3has a function of relaying the sheet Sh1from the main body1to the extension device2. In the present embodiment, focusing on the relationship between the extension device2and the relay conveying unit3, the extension device2is a downstream unit, and the relay conveying unit3is an upstream unit. In addition, focusing on the relationship between the relay conveying unit3and the main body1, the relay conveying unit3is a downstream unit, and the main body1is an upstream unit.

Here, the first conveying portion11is separately provided in the main body1and the relay conveying unit3. Specifically, a third conveying path L3is formed in the relay conveying unit3, and the first conveying path L1of the main body1and the second conveying path L2of the extension device2are continuously connected by the third conveying path L3. That is, the conveying path L10has the first conveying path L1, the third conveying path L3, and the second conveying path L2in this order from the upstream side.

In the present embodiment, the first conveying portion11has a plurality of pairs of first conveying rollers111and a plurality of pairs of second conveying rollers112. A plurality of pairs (three pairs as an example) of the first conveying rollers111are disposed on the third conveying path L3of the relay conveying unit3, and a plurality of pairs (four pairs as an example) of the second conveying rollers112are disposed on the first conveying path L1of the main body1. A second loop space Sp2is provided between the plurality of pairs of first conveying rollers111and the plurality of pairs of second conveying rollers112, as in the first embodiment. In the present embodiment, as an example, the second loop space Sp2is disposed at the upstream end of the third conveying path L3, that is, at a position where the third conveying path L3connects to the first conveying path L1of the upstream unit (the main body1in the present embodiment). Here, since the second loop space Sp2is located at an introduction part (introduction port) of the sheet Sh1in the third conveying path L3, the second loop space Sp2is located immediately after the second conveying roller112.

Also in the image processing apparatus10A according to the present embodiment, there is an advantage that the deflection of the sheet Sh1is easily stabilized when correcting the skew of the sheet Sh1, as in the first embodiment.

As a modification of the second embodiment, the registration roller221may be provided in the relay conveying unit3. In this case, the mechanical registration correction is executed in the relay conveying unit3. In addition, another extension device2may be installed between the relay conveying unit3and the extension device2. In addition, the second loop space Sp2may be formed in the main body1instead of the relay conveying unit3, or may be formed so as to be dispersed in the relay conveying unit3and the main body1. In addition, only one pair of the first conveying rollers111and one pair of the second conveying rollers112may be provided. The configuration (including the modification) of the second embodiment can be applied in combination with each configuration (including the modification) described in the first embodiment.

Appendixes of Invention

The following are appendixes to the overview of the invention extracted from the above embodiments. It is noted that the structures and processing functions to be described in the following appendixes can be selected and combined arbitrarily.

An image processing apparatus comprising:a registration roller disposed on a conveying path of a sheet to be subjected to image processing and configured to correct a skew of the sheet by allowing a leading end of the sheet to abut thereon in a stopped state;a first conveying roller disposed upstream of the registration roller on the conveying path at a position where a first loop space for deflecting the sheet is interposed between the first conveying roller and the registration roller and configured to convey the sheet at a first conveying speed; anda second conveying roller disposed upstream of the first conveying roller on the conveying path at a position where a second loop space for deflecting the sheet is interposed between the second conveying roller and the first conveying roller and configured to convey the sheet at a second conveying speed that is equal to or higher than the first conveying speed.

The image processing apparatus according to Appendix 1, comprising:a downstream unit including the registration roller; andan upstream unit including the first conveying roller, whereinthe conveying path is formed to be continuous from the upstream unit to the downstream unit.

The image processing apparatus according to Appendix 1 or 2, whereinthe second conveying roller accelerates the second conveying speed after the sheet passes through an image processing portion configured to perform the image processing on the sheet.

The image processing apparatus according to any one of Appendixes 1 to 3, whereinduring an acceleration period from when the registration roller is in the stopped state to when the registration roller reaches a predetermined conveying speed, a deflection length of the sheet generated in the first loop space due to a difference in conveying speed between the registration roller and the first conveying roller is larger than a deflection length of the sheet generated in the second loop space due to a difference between the first conveying speed and the second conveying speed.

The image processing apparatus according to any one of Appendixes 1 to 4, whereinthe first conveying roller is capable of changing the first conveying speed.

The image processing apparatus according to Appendix 5, whereinthe first conveying roller changes the first conveying speed in accordance with a conveying speed of the registration roller.