JP2019167170A - Image forming device - Google Patents

Abstract

To suppress skew of a sheet caused by inclination of a roller.SOLUTION: The image forming device comprises: a register roller comprising at least two partial rollers arranged side by side along a conveyance orthogonal direction which is a direction orthogonal to the conveyance direction in a sheet in a conveyance plane of the conveyed sheet; at least one conveyance roller that is disposed downstream of the register rollers in the conveyance direction of the sheet and conveys the sheet; a driving device provided corresponding to each partial roller and having a motor that drives each partial roller independently at a target speed; and a control device connected to the driving device. The driving device outputs an operation amount when the partial roller is driven at the target speed to the control device. The control device determines that the register roller or the conveyance roller is inclined with respect to the conveyance orthogonal direction based on the difference in the operation amount output from the driving device.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus.

  In general, a sheet-like recording medium such as a sheet conveyed in the image forming apparatus (which may be simply referred to as “sheet” in the following description) has a leading edge and a trailing edge of the sheet with respect to the conveying direction. Ideally, the edges are conveyed perpendicularly and the side edges are parallel. If the sheet is skewed at an image forming position such as a transfer position where an image is transferred to the sheet, the image formed on the sheet may be disturbed. Further, if the degree of skew is large, in addition to image distortion, the sheet may be wrinkled or the sheet may be torn.

  In Japanese Patent Laid-Open No. 2004-133260, the skew of the paper is corrected by independently controlling the conveying means arranged in parallel in the conveying width direction of the recording material (sheet) based on the detection result of the detecting means for detecting the skew. An image forming apparatus is disclosed.

JP 2008-233330 A

  By the way, there are a registration roller, a transfer roller, a fixing roller, and a paper discharge roller, for example, as the rollers for conveying the sheets arranged before and after the transfer position. These rollers are arranged so that the axial direction thereof coincides with a direction perpendicular to the sheet conveyance direction (hereinafter, also referred to as “conveyance orthogonal direction”) in the conveyance plane of the sheet to be conveyed. Ideally. When the axial direction of any roller is inclined with respect to the conveyance orthogonal direction, that is, when any roller is inclined, the sheet passing through the inclined roller may be skewed. is there. For example, when the transfer roller is tilted with respect to the conveyance orthogonal direction, even if the skew of the sheet is corrected by the registration roller, the sheet is skewed as it passes the transfer roller, and the sheet is moved to the rear end portion of the sheet in the conveyance direction There is a possibility that an image to be formed is disturbed.

  However, the image forming apparatus disclosed in Patent Document 1 cannot suppress the skew of the sheet due to the inclination of the roller.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of suppressing sheet skew caused by the inclination of a roller.

In order to solve the above-described problems and achieve the object of the present invention, the image forming apparatus of the present invention is arranged along the conveyance orthogonal direction, which is a direction orthogonal to the conveyance direction of the sheet, on the conveyance plane of the conveyed sheet. A registration roller comprising at least two partial rollers arranged;
At least one conveyance roller that is arranged downstream of the registration rollers in the sheet conveyance direction, and is provided corresponding to each partial roller, and a motor that drives each partial roller independently at a target speed. And a control device connected to the drive device, the drive device outputs an operation amount when the partial roller is driven at the target speed to the control device. Based on the output operation amount difference, it is determined that the registration roller or the transport roller is inclined with respect to the transport orthogonal direction.

According to the present invention, it is possible to suppress the skew of the sheet due to the inclination of the roller.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a diagram illustrating an outline of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration example of the image forming apparatus in FIG. 1. It is a figure for demonstrating the registration roller which concerns on embodiment of this invention. It is a figure which shows the speed fluctuation | variation of a registration roller. It is a figure for demonstrating the force which acts when a secondary transfer roller inclines. It is a figure which shows the fluctuation | variation of the operation amount which the 1st motor control circuit and the 2nd motor control circuit computed. It is a figure which shows the relationship between the difference of operation amount, and the shift | offset | difference of a roller. It is a figure which shows an example of the table for deviation | shift amount measurement.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.

[Outline of image forming apparatus]
First, an outline of the image forming apparatus according to the present embodiment will be described with reference to FIGS. 1 and 2.
FIG. 1 is a diagram showing an outline of the image forming apparatus 1. FIG. 2 is a block diagram illustrating a configuration example of the image forming apparatus 1.

  As shown in FIGS. 1 and 2, the image forming apparatus 1 includes a control unit 11, a storage unit 12, a paper transport unit 13, an operation unit 14, a display unit 15, a communication unit 16, an image processing unit 17, and an image forming unit 18. The image reading unit 19 is provided. The image forming apparatus 1 includes a paper feeding unit 20 and a paper discharge unit 21. These are connected to each other by an internal bus.

  The control unit 11 includes a CPU (Central Processing Unit) 11a and a memory such as a ROM (Read Only Memory) 11b and a RAM (Random Access Memory) 11c. The CPU 11a reads a program for controlling the operation of the image forming apparatus 1 from the ROM 11b or the storage unit 12, and develops and executes the program on the RAM 11c.

  The control unit 11 executes an alignment adjustment process for adjusting the alignment of various rollers that convey the sheet to which the image is transferred. The alignment adjustment process will be described later. The “sheet” in the present embodiment includes not only paper “paper” but also a resinous thin film or thin plate material, article, or printed matter. In the following description, “paper” will be described as an example of the sheet.

The image reading unit 19 reads an image of a document set on a document table by a user.
The control unit 11 causes the image processing unit 17 to perform image processing on the document data and the scanned image data received from the external device, and causes the image forming unit 18 to form an image on the sheet based on the image data after the image processing.

  The storage unit 12 is composed of a large-capacity memory composed of a magnetic disk such as a rewritable hard disk. The storage unit 12 stores a program that can be read by the control unit 11, data used when the program is executed, and the like. For example, the data stored in the storage unit 12 includes a deviation amount measurement table (see FIG. 8) used for an alignment adjustment process described later. The deviation amount measurement table will be described later.

The operation unit 14 and the display unit 15 are provided as a user interface above the image forming apparatus 1.
The operation unit 14 generates an operation signal corresponding to a user operation and outputs the operation signal to the control unit 11. Examples of the operation unit 14 include a key and a touch panel configured integrally with the display unit 15.

  The display unit 15 displays an operation screen and various information according to instructions from the control unit 11. As the display unit 15, an LCD (Liquid Crystal Display), an OELD (Organic Electro Luminescence Display), or the like can be used.

  The communication unit 16 communicates with external devices on a network such as a user terminal, a server, and other image forming apparatuses. For example, the communication unit 16 receives document data described in a page description language (PDL) from a user terminal via a network.

  The image processing unit 17 is configured by an integrated circuit such as an ASIC (Application Specific Integrated Circuit). The image processing unit 17 converts bitmap format image data having gradation values for each pixel into C (cyan), M (magenta), and Y (yellow) based on document data described in a page description language. And K (black) for each color. The image processing unit 17 also uses a bitmap format for each color of C (cyan), M (magenta), Y (yellow), and K (black) based on the scanned image data of the document read by the image reading unit 19. Image data is generated.

The image processing unit 17 performs necessary image processing, such as gradation processing and halftone processing, on the generated image data.
The gradation process is a process of converting the gradation value of each pixel into a gradation value corrected so that the density characteristic of the image formed on the paper matches the target density characteristic. The halftone processing is, for example, error diffusion processing, screen processing using a systematic dither method, or the like.

The image forming unit 18 forms an image on a sheet according to the gradation value of each pixel of the image data generated by the image processing unit 17.
As shown in FIG. 1, the image forming unit 18 includes four writing units 181, an intermediate transfer belt 182, a secondary transfer roller 183, and a fixing device 184. Each writing unit 181 is arranged in series along the belt surface of the intermediate transfer belt 182. The intermediate transfer belt 182 is wound and rotated by a plurality of support rollers 182a.

  The four writing units 181 form images of C, M, Y, and K colors, respectively. Each writing unit 181 has the same configuration, and includes an exposure unit 18a, a photoreceptor 18b, a developing unit 18c, a charging unit 18d, and a cleaning unit 18e.

  Each writing unit 181 applies a voltage to the photosensitive member 18b by the charging unit 18d and charges it, and then exposes the exposure unit according to the gradation value of each pixel of the image data corresponding to each color C, M, Y, and K. A laser beam is irradiated by 18a to expose the photoreceptor 18b. When each writing unit 181 supplies a color material such as toner from the developing unit 18c and develops the electrostatic latent image formed on the photoreceptor 18b, an image of each color is formed on the photoreceptor 18b of each writing unit 181. Is done.

  The images on the respective photoconductors 18b are sequentially transferred onto the intermediate transfer belt 182, and an image having a plurality of colors (hereinafter, these may be referred to as “toner images”) is formed on the intermediate transfer belt 182. Is done. After the transfer, each writing unit 181 removes the color material remaining on the photoreceptor 18b after the transfer by the cleaning unit 18e.

  The secondary transfer roller 183 includes one of a plurality of support rollers 182a and a counter roller 182b facing the intermediate transfer belt 182 via the intermediate transfer belt 182. As the sheet passes through the secondary transfer roller 183, the toner image on the intermediate transfer belt 182 is secondarily transferred to the sheet.

  The sheet on which the unfixed toner image is formed is conveyed to the fixing device 184. The fixing device 184 includes a fixing roller 184c including a heating roller 184a that heats one side of the paper on which the toner image is formed and melts the toner, and a pressure roller 184b. The fixing device 184 heats and presses the paper that passes through the fixing roller 184c to fix the toner image on the paper.

  The paper feed unit 20 includes a paper feed tray 201 and a manual paper feed unit 202. In the paper feed tray 201, paper identified based on basis weight, size, or the like is stored for each preset paper type.

  The paper discharge unit 21 has a paper discharge roller 211 and the like, and discharges the paper sent from the paper transport unit 13 to the outside of the apparatus.

  The sheet conveying unit 13 includes a main sheet passing path unit 131, a switchback path unit 132, a back surface printing path unit 133, a sheet passing path switching unit 134, and the like. The main sheet passing path unit 131 includes a plurality of rollers that sandwich and convey the sheet. The plurality of rollers include a registration roller 135 disposed on the upstream side of the secondary transfer roller 183 in the sheet conveyance direction. The plurality of rollers includes an upstream roller 136 disposed on the upstream side in the paper transport direction with respect to the registration roller 135.

  The registration roller 135 is used for correcting the inclination of the sheet and adjusting the conveyance timing. The details of the registration roller 135 will be described later with reference to FIG.

  The upstream roller 136 has a separation mechanism 137 (see FIG. 2) that can set the upstream roller 136 in a separated state in which a pair of constituent rollers is separated. The operation of the separation mechanism 137 is controlled by the control unit 11. Since the upstream roller 136 in the separated state cannot pinch the sheet, it cannot apply a conveying force to the sheet.

  The main sheet passing path unit 131 conveys the sheet fed from the sheet feeding tray 201 or the sheet fed via the manual sheet feeding unit 202 and passes the sheet to the image forming unit 18. The paper sent out from the paper is conveyed to the paper discharge unit 21.

  The switchback path unit 132 temporarily stops the paper sent from the fixing device 184, reverses the transport direction, and transports the paper to the paper discharge unit 21 or the back surface printing path unit 133. The back surface printing path unit 133 is a circulation path that conveys the paper that is switched back and sent out by the switchback path unit 132 to the main sheet passing path unit 131. The sheet passing path switching unit 134 is used for switching the sheet passing path.

  Further, the paper transport unit 13 includes a first motor control circuit 138 and a second motor control circuit 139. The first motor control circuit 138 and the second motor control circuit 139 will be described later.

[Registration roller]
Next, details of the registration roller 135 will be described with reference to FIG. FIG. 3 is a view for explaining the registration roller 135 of the present embodiment.

  As shown in FIG. 3, the registration roller 135 includes a first registration roller 135a and a second registration roller 135b, which are two partial rollers, and a base portion 135c that fixes them. The registration roller 135 includes a sensor that detects the inclination of the paper passing through the registration roller 135, and adjusts the rotation speed of the first registration roller 135a and the second registration roller 135b based on the detection result of the sensor. To correct the skew of the paper.

  The first registration roller 135a and the second registration roller 135b fixed to the base portion 135c are arranged side by side in the sheet conveyance orthogonal direction. Further, the first registration roller 135a and the second registration roller 135b are arranged so as to be symmetrical with respect to the center in the conveyance orthogonal direction of the paper passing through the registration roller 135. Further, the first registration roller 135a and the second registration roller 135b have the same diameter and are arranged so that the rotation axis is coaxially arranged.

  The first registration roller 135a is driven by a motor (drive device) M1. The motor M1 is controlled by the first motor control circuit 138. The first motor control circuit 138 is connected to the control unit 11. The first motor control circuit 138 controls the motor M1 according to the instruction from the control unit 11 so that the rotation speed (axial speed) of the roller shaft of the first registration roller 135a is constant at the target speed. The first motor control circuit 138 has a sensor that detects the rotational speed of the roller shaft of the first registration roller 135a, compares the detection result of this sensor with the target speed, and rotates the rotational speed of the roller shaft (axial speed). ) Are operated such as voltage and PWM value so that they match the target speed. Then, the motor M1 is driven according to the calculated operation amount. That is, the first motor control circuit 138 performs PI control (Proportional and Integral Control) and PID control (Proportional, Integral and Derivative Control).

  The second registration roller 135b is driven by a motor (drive device) M2. The motor M2 is controlled by the second motor control circuit 139. The second motor control circuit 139 is connected to the control unit 11. The second motor control circuit 139 controls the motor M2 in accordance with an instruction from the control unit 11 so that the rotation speed (axial speed) of the roller shaft of the second registration roller 135b is constant at the target speed. The second motor control circuit 139 has a sensor that detects the rotational speed of the roller shaft of the second registration roller 135b. Note that the mode of driving control of the motor M2 of the second motor control circuit 139 is the same as the mode of driving control of the motor M1 of the first motor control circuit 138 described above, and thus the description thereof is omitted here.

  Each of the first motor control circuit 138 and the second motor control circuit 139 sequentially outputs the calculated operation amount to the control unit 11.

  The base part 135c is provided with an adjustment mechanism A1. The adjustment mechanism A1 adjusts the inclination of the axes of the first registration roller 135a and the second registration roller 135b fixed to the base portion 135c with respect to the conveyance orthogonal direction. The adjustment mechanism A1 has a dial (not shown), and when the dial is rotated clockwise once, the registration roller 135 has the other end (lower end in FIG. 3) centered on one end (the upper end in FIG. 3). Side end) rotates clockwise once. On the other hand, when the dial is rotated counterclockwise once, the other end of the registration roller 135 is rotated counterclockwise once.

  Each of the secondary transfer roller 183, the fixing roller 184c, and the paper discharge roller 211 is provided with adjustment mechanisms A2, A3, and A4 that adjust the inclination of each axis with respect to the conveyance orthogonal direction, similarly to the adjustment mechanism A1. ing.

[Alignment adjustment processing]
Next, alignment adjustment processing executed by the control unit 11 will be described with reference to FIGS. FIG. 4 is a diagram showing the speed fluctuation of the registration roller. FIG. 5 is a diagram for explaining the force acting when the secondary transfer roller is tilted. FIG. 6 is a diagram illustrating fluctuations in the operation amount calculated by the first motor control circuit and the second motor control circuit. FIG. 7 is a diagram illustrating the relationship between the difference in the operation amount and the deviation of the roller. FIG. 8 is a diagram illustrating an example of the deviation amount measurement table.

  For example, when the image forming apparatus 1 is installed, the alignment adjustment process is executed when an installation operator performs initial settings. In the alignment adjustment process, the control unit 11 transports the registration roller 135, the secondary transfer roller 183, the fixing roller 184c, and the paper discharge roller 211 in the present embodiment, among the rollers (transport rollers) having a function of transporting paper. The amount of inclination (deviation) with respect to the orthogonal direction (may be referred to as “deviation amount” in the following description) is measured. Moreover, the control part 11 specifies the adjustment amount corresponding to the measured deviation | shift amount.

  In the alignment adjustment process, as will be described later, the first motor control circuit 138 and the first motor control circuit 138 and the first motor control circuit 138 when the front end side in the paper transport direction passes the measurement target roller in a state where the registration roller 135 sandwiches and transports the paper. The difference in the operation amount output from the 2-motor control circuit 139 is used. For this reason, the paper used for the alignment adjustment process is a paper having a length in the transport direction that is longer than the distance between the registration roller 135 and the roller to be measured. In the present embodiment, the length in the transport direction of the paper stored in the paper feed tray 201 is the registration roller 135 and the discharge roller 211 that is farthest from the registration roller 135 among the rollers to be measured. The paper stored in the paper feed tray 201 is used. On the other hand, when there is no suitable paper in the paper feed tray 201, the operator removes a paper having a length in the transport direction longer than the distance between the registration roller 135 and the measurement target roller from the manual paper feed unit 202. Feed paper.

  When the alignment adjustment process is executed, the control unit 11 causes the first motor control circuit 138 to move the motor M1 so as to rotate the first registration roller 135a and the second registration roller 135b at the same target speed, as shown in FIG. And the second motor control circuit 139 controls the motor M2. Then, the control unit 11 sequentially compares the operation amounts output from the first motor control circuit 138 and the second motor control circuit 139.

  As shown in FIG. 5, for example, when the secondary transfer roller 183 is tilted with respect to the conveyance orthogonal direction, it is a side end portion of the sheet on the side where the distance between the secondary transfer roller 183 and the registration roller 135 is short. There is a case where bending occurs on the side end (upper side end in FIG. 5) side. Along with the occurrence of the bending, a reaction force is generated in the direction indicated by the arrow Y1 in FIG.

  As described above, when a reaction force is generated on one side edge (upper side edge in FIG. 4) of the sheet, the motor M1 requires a larger driving force than the motor M2. For this reason, as shown in FIG. 6, there is a difference between the operation amount calculated by the first motor control circuit 138 and the operation amount calculated by the second motor control circuit 139. Specifically, the operation amount calculated by the first motor control circuit 138 is larger than the operation amount calculated by the second motor control circuit 139.

  The control unit 11 sequentially calculates a difference in operation amount until the paper passes through the registration roller 135, the secondary transfer roller 183, the fixing roller 184c, and the paper discharge roller 211 and is discharged. And the control part 11 specifies the roller which has generate | occur | produced the shift | offset | difference based on a calculation result.

  Specifically, the control unit 11 detects the position of the sheet based on the elapsed time since the conveyance of the sheet from the registration roller 135 is started, and a deviation occurs based on the difference in the operation amount at each sheet position. Identify the roller that is running.

  For example, as shown in Example 1 of FIG. 7, when the secondary transfer roller 183 is misaligned, a difference occurs in the operation amount when the sheet starts to pass through the secondary transfer roller 183 (the operation amount at this time). Is referred to as “difference A”). Thereafter, when the sheet starts to pass through the fixing roller 184c, the difference in the operation amount changes from the difference A due to the difference between the inclination of the secondary transfer roller 183 in the conveyance orthogonal direction and the inclination of the fixing roller 184c in the conveyance orthogonal direction. (The difference in the operation amount at this time is referred to as “difference B”). Even if the paper starts to pass through the paper discharge roller 211, there is no difference in the inclination in the conveyance orthogonal direction between the fixing roller 184c and the paper discharge roller 211. Therefore, the difference in the operation amount remains the difference B. Become. In such a case, the control unit 11 identifies the roller in which the deviation has occurred as the secondary transfer roller 183.

  Further, as shown in Example 2 in FIG. 7, when the fixing roller 184c is misaligned, there is no difference in the operation amount until the paper starts to pass through the fixing roller 184c. When the sheet starts to pass through the fixing roller 184c, a difference occurs in the operation amount (the difference in the operation amount at this time is referred to as “difference C”). Thereafter, when the sheet starts to pass through the paper discharge roller 211, the difference in the operation amount changes from the difference C due to the difference between the inclination of the fixing roller 184c in the conveyance orthogonal direction and the inclination of the paper discharge roller 211 in the conveyance orthogonal direction. (The difference in the operation amount at this time is referred to as “difference D”). In such a case, the control unit 11 identifies the roller in which the deviation has occurred as the fixing roller 184c.

  Further, as shown in Example 3 in FIG. 7, when the registration roller 135 is misaligned, when the sheet starts to pass through the secondary transfer roller 183, the registration roller 135 is inclined in the conveyance orthogonal direction and the secondary direction. Due to the difference from the inclination of the transfer roller 183 in the conveyance orthogonal direction, a difference occurs in the operation amount (the difference in operation amount at this time is referred to as “difference E”). After that, even if the paper starts to pass through the fixing roller 184c, there is no difference in the inclination in the conveyance orthogonal direction between the secondary transfer roller 183 and the fixing roller 184c. Become. Even when the paper starts to pass through the paper discharge roller 211, there is no difference in the inclination in the conveyance orthogonal direction between the fixing roller 184c and the paper discharge roller 211, so the difference in the operation amount remains the difference E. Become. In such a case, the control unit 11 identifies the roller in which the deviation has occurred as the registration roller 135.

  Although illustration is omitted, when the paper discharge roller 211 is misaligned, there is no difference in the operation amount until the paper starts to pass through the paper discharge roller 211. When the passage starts, there is a difference in the operation amount. . In such a case, the control unit 11 identifies the roller in which the deviation has occurred as the paper discharge roller 211.

  After identifying the roller in which the deviation has occurred, the control unit 11 refers to the deviation amount measurement table (see FIG. 8) stored in the storage unit 12 for the identified roller, and measures the deviation amount.

  The displacement amount measurement table is provided for each type of roller (registration roller 135, secondary transfer roller 183, fixing roller 184c, paper discharge roller 211), and the difference in operation amount, displacement amount (angle), and displacement are adjusted. It defines the correspondence between adjustment amounts for correction. FIG. 8 shows an example of a deviation amount measurement table related to the secondary transfer roller 183 that is referred to when the secondary transfer roller 183 is specified as the roller in which the deviation has occurred. The deviation amount measurement table is prepared in advance based on experiments and simulations for measuring the difference in the operation amount in a state where the deviation is generated. For example, the deviation value “1” and the adjustment value “1” are associated with the operation amount difference value “1”.

  In this embodiment, the amount of misalignment is the angle between a straight line extending in the conveyance orthogonal direction from one end of the rotation axis of the roller (the upper end in FIG. 5) when the image forming apparatus 1 is viewed from above and the rotation axis of the roller. (Indicated by an angle K in FIG. 5).

  In the present embodiment, the angle for rotating the dials of the adjustment mechanisms A1, A2, A3, and A4 (the positive value is clockwise and the negative value is counterclockwise) is defined as the adjustment amount. However, the content of the adjustment amount can be appropriately set according to the configuration of the adjustment mechanism. Further, the value of the difference in the operation amount associated with the deviation amount and the adjustment amount may have a width. For example, the operation amount difference value “1-5” is associated with the displacement amount value “1” and the adjustment amount value “1”, and the operation amount difference value “6-10” is shifted. The amount value “2” and the adjustment amount value “2” may be associated with each other. The adjustment amount may be a rotation angle of a roller necessary for correcting the shift. Also, in experiments and simulations, measure the relationship between the amount of manipulated variable in the state of deviation and the image output result, and specify the adjustment amount so that the image output result is appropriate considering the measurement result. May be. Further, in the present embodiment, the mode in which the deviation amount measurement table is provided for each type of roller has been described. However, a common deviation amount measurement table may be used for some or all of the rollers. Instead of the table, a calculation formula that can calculate the deviation amount and the adjustment amount from the operation amount may be prepared, and the deviation amount and the adjustment amount may be calculated.

  Next, the control unit 11 causes the display unit 15 to display information on the roller specified as the roller in which the deviation has occurred, and the deviation amount and the adjustment amount measured using the deviation amount measurement table. For example, the display unit 15 indicates that “the secondary transfer roller is shifted by 10 degrees (clockwise when viewing the image forming apparatus from the information). Please rotate the dial counterclockwise by 10 degrees”. Display a message. Information to be displayed and a message can be set as appropriate.

[Action]
According to the image forming apparatus 1 of the present embodiment, when any one of the registration roller 135, the secondary transfer roller 183, the fixing roller 184c, and the paper discharge roller 211 is misaligned, the misaligned roller, The display unit 15 displays the shift amount and the adjustment amount for correcting the shift. For this reason, the operator who has seen the display unit 15 can easily adjust the deviation of the rollers. Thus, it is possible to suppress the skew of the sheet due to the inclination (deviation) of the roller, the disturbance of the image, the occurrence of the sheet curl and tear.

  Here, conventionally, when the image forming apparatus is installed, the adjustment of the roller inclination (deviation) is performed by an operator who outputs the adjustment chart, and an adjustment point (deviation occurs based on the output image). Specified roller). Further, it is necessary to repeat the adjustment of the shift and the output of the chart until the output image is within the appropriate range. Furthermore, since the adjustment based on the output image affects all the machine states of the image forming apparatus 1, the image quality is temporarily improved by other measures (for example, adjustment of the shift of the intermediate transfer belt). In some cases, the roller may be left tilted. In this case, since the roller remains tilted (displaced), the image disturbance may recur during use (the image remains affected).

  That is, the accuracy of the conventional adjustment largely depends on the skill of the worker, and the work efficiency is also poor. In the image forming apparatus 1 according to the present embodiment, as described above, the roller in which the deviation occurs, the deviation amount, and the adjustment amount for correcting the deviation are displayed on the display unit 15. Therefore, the adjustment work can be performed accurately and efficiently.

[Modification]
The present invention is not limited to the above-described embodiment, and various other application examples and modifications can of course be taken without departing from the gist of the present invention described in the claims.

  For example, a stepping motor controlled by the control unit 11 is provided in each of the adjustment mechanisms A1, A2, A3, and A4, and the adjustment mechanisms A1, A2, and A3 are automatically performed according to the deviation amount and the adjustment amount measured from the operation amount. , A4 dial may be operated to correct the deviation.

  In the above description of the embodiment, an image forming apparatus that forms an image using a plurality of color toners has been described as an example. However, the present invention may be applied to a so-called monochrome machine.

  In the description of the above-described embodiment, the aspect in which the registration roller 135 includes the first registration roller 135a and the second registration roller 135b as partial rollers has been described, but three or more partial rollers may be provided. In this case, the amount of deviation may be measured based on the operation amount relating to all the provided partial rollers, or based on the operation amount relating to at least a part (but two or more) of the provided partial rollers. The amount of misalignment may be measured.

  It should be noted that the term “match” in the above description includes substantially match, and the term “orthogonal” includes substantially orthogonal. The term “parallel” includes substantially parallel.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 11 ... Control part (control apparatus) 12 ... Memory | storage part 13 ... Paper conveyance part 14 ... Operation part 15 ... Display part 16 ... Communication part 17 ... Image processing part 18 ... Image Forming unit, 19 ... Image reading unit, 20 ... Paper feeding unit (sheet supply mechanism), 21 ... Paper discharge unit, 131 ... Main paper passage unit, 135 ... Registration roller, 135a ... First registration roller, 135b ... Second Registration roller, 135c: base portion, 136: upstream roller, 137: separation mechanism, 138 ... first motor control circuit, 139 ... second motor control circuit, 182 ... intermediate transfer belt, 182a ... support roller, 182b ... opposite roller, 183 ... Secondary transfer roller, 184 ... Fixing device, 184a ... Heating roller, 184b ... Pressure roller, 184c ... Fixing Ra, 201 ... sheet feed tray, 202 ... manual sheet feeder, 211 ... discharge roller, A1 ... adjusting mechanism, A2 ... adjusting mechanism, M1 ... motor, M2 ... Motor

Claims (5)

A registration roller comprising at least two partial rollers arranged side by side in the conveyance orthogonal direction, which is a direction orthogonal to the conveyance direction in the sheet, in the conveyance plane of the conveyed sheet;
At least one transport roller that is disposed downstream of the registration rollers in the transport direction of the sheet and transports the sheet;
A driving device provided corresponding to each of the partial rollers, and having a motor that independently drives each of the partial rollers at a target speed;
A control device connected to the drive device,
The drive device outputs an operation amount when the partial roller is driven at the target speed to the control device,
The control device determines that the registration roller or the transport roller is inclined with respect to the transport orthogonal direction based on the difference in the operation amount output from the drive device. . The control device determines an adjustment amount for adjusting an inclination of the registration roller or the transport roller with respect to the transport orthogonal direction based on the difference in the operation amount, and notifies the determined adjustment amount. The image forming apparatus according to claim 1. 3. The control device according to claim 2, wherein the control device includes a storage device that stores in advance data in which the difference in the operation amount and the adjustment amount are associated with each other, and determines the adjustment amount based on the data. The image forming apparatus described. Each of the registration roller and the transport roller includes an adjustment mechanism that adjusts an inclination with respect to the transport orthogonal direction,
The image forming apparatus according to claim 2, wherein the control device controls the adjustment mechanism in accordance with the determined adjustment amount. A sheet supply mechanism for supplying a sheet longer than the length between the registration roller and the transport roller;
An upstream roller that is disposed upstream of the registration roller in the conveyance direction of the sheet and conveys the sheet to the registration roller, and
The control device arranges the upstream roller at a position away from the paper until the leading end in the sheet conveyance direction reaches the registration roller until the trailing end in the same direction passes the registration roller, The image forming apparatus according to claim 1, wherein the sheet is conveyed by a roller.

Images