JP2018028565A - Image forming apparatus and image formation control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute proper color registration adjustment without stopping an image forming operation in execution.SOLUTION: An image forming apparatus comprises: an image forming part that forms an image by transferring, to a sheet, images formed on image carriers by using a plurality of colors of color materials; and a control part that controls image formation performed by the image forming part. The control part has a color material discharge function to select less-used color materials as discharge color materials according to the use state of the color materials for every color, and form specific patterns on the image carriers by using the discharge color materials to discharge the discharge color materials. The control part controls the image forming part to form the specific patterns with the plurality of color materials: the plurality of discharge color materials; or the discharge color material and a non-discharge color material not selected by the color material discharge function, and perform registration adjustment from a result of detection of the positions of the plurality of color materials in the specific patterns.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer and an image forming control program, and more particularly to an image forming apparatus having a registration adjustment function and an image forming control program.

As an image forming apparatus, an image carrier such as a photosensitive drum is driven in the sub-scanning direction, and exposure by scanning (main scanning) for one line or a plurality of lines in the main scanning direction according to image data is repeatedly performed. One that performs two-dimensional (every page) image formation is known.
The color image forming apparatus uses color materials of a plurality of colors (for example, ink and toner, in this specification, “toner” is used as a specific example of the color material in the electrophotographic image forming apparatus). It is necessary to accurately superimpose a toner image formed on a color image carrier on an intermediate transfer member such as an intermediate transfer belt.

  However, the image transfer position with respect to the transfer belt may be shifted between a plurality of colors due to machine accuracy, transfer belt speed fluctuation, and the like. Also, due to temperature changes, the distance between the image carriers for each color and the length of the transfer belt also change, and the distance, magnification (size) and position between the colors change, and the image on the transfer belt between the colors. The transfer position may shift.

  That is, the color misregistration appears as color misregistration. In order to prevent this color misregistration, a color misregistration measurement pattern (hereinafter referred to as “color resist pattern”) is formed on the transfer belt, and color misregistration correction is performed based on the detection result of this color resist pattern. (Hereinafter referred to as “registration adjustment”).

In addition, as the color resist pattern at the time of color resist adjustment, various types of misregistration that can cause color misregistration in each color, that is, misregistration in the main scanning direction, misregistration in the sub scanning direction, inclination, and magnification deviation are detected. A pattern is used.
In this case, it is necessary to form and read patterns of several to several tens of sheets in the rotation direction of the image carrier in terms of normal standard size paper. For this reason, if it is executed during image formation, it cannot be executed between images, and it is necessary to interrupt the image formation.

  The following patent documents disclose various techniques for resist adjustment in an image forming apparatus.

JP 2010-197586 A

  The start timing of registration adjustment in a general color image forming apparatus is adjustment at power-on, time-dependent adjustment (when a predetermined internal temperature (Δ3 ° C.) changes), and the like. Note that the power-on adjustment and the time-dependent adjustment use a color resist dedicated pattern, and therefore, the printing operation is stopped.

In the case of such an image forming apparatus, the temperature becomes stable after several hours have elapsed in the continuous use state, so that the time adjustment is not performed.
However, depending on the meandering of the intermediate transfer belt and the change of the primary / secondary transfer position of each color, an image inclination called skew deviation may occur over time during image formation.

  In such a case, the start timing of the time adjustment can be defined by the number of prints so that the time adjustment is executed. However, this method forcibly activates the time adjustment even when correction is not required. This causes a new problem that the image formation interruption (downtime) due to the time adjustment during image formation increases. To do.

In Patent Document 1 described above, a pattern used for stabilization correction (gamma correction or maximum density correction) or a pattern dedicated to resist adjustment is created for calibration, and the print operation is stopped to perform resist adjustment. To implement.
That is, in the conventional image forming apparatus, there is a problem that when the image forming operation is being executed, the color registration adjustment cannot be executed without stopping the image forming being executed.

  The present invention has been made in view of such a problem, and provides an image forming apparatus and an image forming control program capable of executing appropriate color registration adjustment without stopping an image forming operation being executed. It aims to be realized.

In order to solve the above-described problems, an image processing apparatus and an image formation control program reflecting one aspect of the present invention are configured as follows.
(1) The present invention provides an image forming unit that forms an image by transferring an image formed on an image carrier using a plurality of color materials onto a sheet, and a sensor that detects the color material in the image forming unit. And an image forming apparatus that controls image formation by the image forming unit, wherein the control unit discharges a low-use color material in accordance with a use situation of each color of the color material. Select as a color material, have a color material discharge function to discharge the discharged color material by forming a specific pattern on the image carrier using the discharged color material, the discharged color materials, or the The specific pattern is formed by a plurality of the color materials, which are not selected by the color material discharge function and the non-discharge color material, and a resist is detected by a detection result of positions between the color materials in the specific pattern. The image forming unit is controlled to make adjustments. To, characterized in that.

  The image forming control program according to the present invention is an image forming unit that forms an image by transferring an image formed on an image carrier using a plurality of color materials onto a sheet, and according to the usage status of each color material. Selecting a low-use color material as a discharge color material, having a color material discharge function for discharging the discharge color material by forming a specific pattern on the image carrier using the discharge color material, The specific pattern is formed by any of the plurality of color materials of the discharge color materials or the non-discharge color material that is not selected by the color material discharge function and the discharge color material, and the plurality of colors in the specific pattern The computer of the image forming apparatus is caused to function as a control unit that controls the image forming unit to perform registration adjustment based on the detection result of the position between the materials.

(2) In the above (1), the control unit determines a color material serving as a reference for the resist adjustment among the plurality of color materials included in the specific pattern in accordance with a predetermined priority order. It is characterized by that.
(3) In the above (1) to (2), the control unit determines a reference color material at the time of the registration adjustment according to the priority order according to the arrangement of the image carrier in the image forming unit. It is characterized by that.

  (4) In the above (1) to (3), when the specific pattern is formed by the discharge color material and the non-discharge color material, the control unit is more than the specific pattern by the discharge color material. Control is performed such that the area of the specific pattern by the non-discharged color material is reduced.

  (5) In the above (1) to (4), the control unit refers to the measurement result of the resist adjustment in the color material on which the specific pattern is formed, and corrects the color material on which the specific pattern is not formed. The registration adjustment is applied by calculating data.

(6) In the above (1) to (5), the control unit is configured such that the specific pattern by the discharged color material has a shape or an area corresponding to a discharge amount required by the color material discharge function. Features.
(7) In the above (1) to (6), the control unit discharges the discharged color material without interrupting the image forming operation being performed, and forms the image so as to perform the registration adjustment. Part is controlled.

  (8) In the above (1) to (7), as the resist adjustment, the control unit performs a first resist adjustment for performing adjustment based on an adjustment dedicated pattern corresponding to a plurality of inspection items, and the first resist. Forming a specific pattern on the image carrier having a function of selecting and executing any one of the second resist adjustment for performing adjustment based on the specific pattern corresponding to inspection items smaller than the adjustment; And discharging the discharged color material and controlling the image forming unit to perform the second resist adjustment.

  (9) In the above (8), when the rotation direction of the image carrier is a sub-scanning direction and the direction perpendicular to the sub-scanning direction on the surface of the image carrier is a main scanning direction, the control unit The image forming unit is controlled to perform the first resist adjustment for detecting the main scanning direction positional deviation, the sub-scanning direction positional deviation, the inclination, and the magnification deviation by using the adjustment dedicated pattern, and the specific pattern is determined. And the image forming unit is controlled to perform the second registration adjustment for detecting the positional deviation and inclination in the sub-scanning direction.

According to the image processing apparatus and the image formation control program reflecting one aspect of the present invention, the following effects can be obtained.
(1) In the image forming apparatus and the image forming control program according to the present invention, a specific pattern is formed by the color material discharge function based on the color material use status in image formation, and the color material is discharged. Since the registration adjustment is performed using the specific pattern, registration adjustment can be performed between images during image formation, and appropriate color registration adjustment can be performed without stopping the image forming operation being executed.

  (2) In the above (1), in order to determine a color material as a reference for resist adjustment among a plurality of color materials included in the specific pattern according to a predetermined priority order, Thus, accurate registration adjustment can be performed, and appropriate color registration adjustment can be executed without stopping the image forming operation being executed.

  (3) In the above (1) to (2), since a reference color is determined at the time of registration adjustment in accordance with the priority order according to the arrangement of the image carrier in the image forming unit, between images during image formation. Accurate registration adjustment is possible, and appropriate color registration adjustment can be executed without stopping the image forming operation being executed.

(4) In the above (1) to (3), when the specific pattern is formed by the discharge color material and the non-discharge color material, the area of the specific pattern by the non-discharge color material is larger than the specific pattern by the discharge color material. Since it is controlled to be small, it is possible to adjust the registration between images during image formation.
Appropriate color registration adjustment can be executed without stopping the image forming operation being executed.

  (5) In the above (1) to (4), with reference to the measurement result of the resist adjustment in the color material on which the specific pattern is formed, the correction data for the color material on which the specific pattern is not formed is calculated and calculated. Since the adjustment is applied, it is possible to perform registration adjustment by using color material between images during image formation without waste, and it is possible to perform appropriate color registration adjustment without stopping the current image formation operation. become.

  (6) In the above (1) to (5), the specific pattern by the discharged color material has a shape or area corresponding to the required discharge amount by the color material discharge function. Registration adjustment can be performed using materials without waste, and appropriate color registration adjustment can be executed without stopping the image forming operation being executed.

  (7) In the above (1) to (6), the discharged color material is discharged without interrupting the image forming operation being performed, and the image forming unit is controlled so as to perform registration adjustment. Registration adjustment between images can be performed during formation, and appropriate color registration adjustment can be executed without stopping the image forming operation being executed.

  (8) In the above (1) to (7), as the resist adjustment, the first resist adjustment for adjusting based on the adjustment-dedicated pattern corresponding to a plurality of inspection items, and the inspection items less than the first resist adjustment. A function of selecting and executing any one of the second resist adjustments that are adjusted based on the corresponding specific pattern, and discharging the discharged color material by forming the specific pattern on the image carrier, Since the image forming unit is controlled to perform the second resist adjustment, the second resist adjustment can be performed between images during image formation, and an appropriate color resist adjustment is performed without stopping the image forming operation being performed. It becomes possible.

  (9) In the above (8), using the adjustment-dedicated pattern, using the first resist adjustment for detecting the main scanning direction positional deviation, the sub-scanning direction positional deviation, the inclination, and the magnification deviation, and the specific pattern, Since the second registration adjustment for detecting positional deviation and inclination in the sub-scanning direction is selected and performed, precise registration adjustment is possible with the adjustment-dedicated pattern except during image formation, and between images during image formation. By using the specific pattern, it is possible to perform simple color registration adjustment without stopping the image forming operation being executed.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present invention. 3 is a flowchart illustrating an overall operation of the image forming apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating an operation of a characteristic portion of the image forming apparatus according to the embodiment of the present invention. It is explanatory drawing which shows the pattern used by adjustment of embodiment of this invention. FIG. 6 is an explanatory diagram illustrating an operation state of the image forming apparatus according to the embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating an operation state of the image forming apparatus according to the embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating an operation state of the image forming apparatus according to the embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating an operation state of the image forming apparatus according to the embodiment of the present invention.

  Hereinafter, an image forming apparatus and an image forming control program will be described in detail as modes for carrying out the present invention (hereinafter referred to as embodiments) with reference to the drawings. In the following description, the image forming apparatus will be mainly described, but the control unit of the image forming apparatus proceeds with processing according to the image forming control program.

〔Constitution〕
The configuration of the image forming apparatus according to the present embodiment will be described with reference to the block diagram of FIG. 1 and the configuration diagram of FIG.
The image forming apparatus 100 includes a control unit 101, a communication unit 102, an operation display unit 103, a storage unit 104, a paper feeding unit 105, a transport unit 110, an image data storage unit 130, an image processing unit 140, an image forming unit 150, a registration sensor. 160 and a paper discharge unit 190.

  The control unit 101 controls each unit in the image forming apparatus 100. The communication unit 102 communicates with other devices. The operation display unit 103 notifies the control unit 101 of an operation input signal corresponding to the operation input by the user and displays the status of the image forming apparatus 100. The storage unit 104 stores a control program and various setting data and is used as a work area for the control program. Note that the storage unit 104 of this embodiment stores patterns necessary for registration adjustment and toner disposal. The paper feeding unit 105 feeds the stored paper. The paper feeding unit 105 can feed one or both of a standard size paper and a roll type long paper. The transport unit 110 transports paper that is fed and printed at a predetermined speed. The image data storage unit 130 stores image data and various data for printing. The image processing unit 140 executes various image processes necessary for printing.

  The image forming unit 150 executes image formation (which means a series of operations such as image formation, transfer, and fixing, and is collectively referred to as “print”) based on the print command and the image data after image processing. Further, the image forming unit 150 forms a pattern for resist adjustment on the image carrier or the intermediate transfer member between the image regions (between images). That is, the print includes both a case where an image is transferred from an intermediate transfer body to a sheet and a case where a specific pattern is formed on the intermediate transfer body for resist adjustment. The registration sensor 160 detects the position and inclination of the pattern formed on the image carrier or intermediate transfer member of the image forming unit 150. The paper discharge unit 190 discharges standard-size paper to a predetermined paper discharge tray, discharges long paper in roll form, and either regular-size paper or roll-long paper. Alternatively, both sheets can be discharged.

  Further, the image forming unit 150 is configured as shown in FIG. Here, a specific example will be described in which toners of four colors of Y (yellow), M (magenta), C (cyan), and K (black) are used as color materials of a plurality of colors. Here, for each color (YMCK) of toner as a color material, the image forming unit 150 includes image carriers 151Y to 151K, charging units 152Y to 152K, exposure units 153Y to 153K, and developing units 154Y to 154K. Intermediate transfer portions 155Y to 155K. The image forming unit 150 includes an intermediate transfer member 157, a transfer unit 158, and a fixing unit 159.

  Further, the charging units 152Y to 152K for the respective colors charge the image bearing members 151Y to 151K for the respective colors at a predetermined potential. Then, electrostatic latent images are formed for the respective colors on the image carriers 151Y to 151K of the respective colors by exposure from the exposure units 153Y to 153K corresponding to the image data of the respective colors. The developing sections 154Y to 154K for the respective colors develop the electrostatic latent images for the respective colors formed on the image carriers 151Y to 151K for the respective colors to form toner images for the respective colors. The intermediate transfer portions 155Y to 155K for the respective colors transfer the respective color toner images on the respective color image carriers 151Y to 151K to the intermediate transfer member 157. In the intermediate transfer member 157, the color toner images on the color image carriers 151Y to 151K are superposed in an aligned state to form a color image. The transfer unit 158 transfers the color image on the intermediate transfer member 157 to a sheet. The fixing unit 159 fixes the toner image on the paper with heat and pressure.

  Note that the registration sensor 160 reads an adjustment-dedicated pattern (see FIG. 6A described later) formed on the intermediate transfer member 157 for registration adjustment, and various types of misregistration that can cause color misregistration in each color, that is, , A main scanning direction position shift, a sub-scanning direction position shift, a tilt, a magnification shift, and the like are detected.

Further, the registration sensor 160 reads a specific pattern (see FIG. 6B described later) formed on the intermediate transfer member 157 for discarding the toner, and relates to various types of misregistration that may cause color misregistration in each color. Then, the positional deviation in the sub-scanning direction is detected.
In the configuration of FIG. 2, the vertical direction in FIG. 2 of the cylindrical image carriers 151 </ b> Y to 151 </ b> K and the belt-shaped intermediate transfer member 157 is defined as the first direction (main scanning direction), and the image carriers 151 </ b> Y to 151 </ b> K. A rotation direction around the central axis of the intermediate transfer member 157 is defined as a second direction (sub-scanning direction).

[Operation (1) of the embodiment]
The operation of the image forming apparatus as the first embodiment and the processing procedure of the image forming control program for controlling the image forming apparatus will be described below with reference to the flowcharts shown in FIGS. To do. In FIG. 5 and subsequent drawings, the positional relationship is schematically shown together with the sensors 160s1 and 160s2 in a state where the intermediate transfer body 157 on which an image or pattern is formed is developed.

Hereinafter, as the first embodiment, registration adjustment when an image is formed using a standard size sheet will be described.
When the image forming apparatus 100 is turned on, the control unit 101 initializes each unit in the image forming apparatus 100 (step S101 in FIG. 3). After the initialization operation is completed, the control unit 101 controls the image forming unit 150 to print the adjustment-dedicated pattern (see FIG. 5A) and execute the first registration adjustment as the power-on adjustment ( Step S102 in FIG. 3).

  The color resist pattern used in the first resist adjustment is for detecting various types of misregistration that can cause color misregistration in each color, that is, misregistration in the main scanning direction, misregistration in the sub scanning direction, inclination, and magnification deviation. The adjustment exclusive pattern shown in FIG. 5A is used. In the case of the first registration adjustment, it is necessary to form and read patterns of several to several tens of sheets in terms of the normal standard size in the sub-scanning direction.

As this adjustment-dedicated pattern, “F” -shaped marks of the same color are formed at respective positions of the registration sensor 160 (160s1, 160s2) in the main scanning direction, and these are sequentially color-coded (K, M, C, Y, K). , M, C, Y,...
Here, since two sensors are arranged in the main scanning direction as the registration sensors 160s1 and 160s2, a plurality of two K marks are formed in the sub-scanning direction at the corresponding sensor position in the main scanning direction. Two C marks are formed in the sub-scanning direction at the corresponding sensor position in the direction, and two M marks are formed in the sub-scanning direction at the corresponding sensor position in the main scanning direction. A plurality of two Y marks are formed in the position in the sub-scanning direction to form one set. Then, this set is sequentially and repeatedly printed in the sub-scanning direction until registration adjustment is completed.

  In the case of this first registration adjustment, the position shift in the sub-scanning direction of the horizontal line of the “F” -shaped mark (line in the main scanning direction) depends on the distance to the horizontal lines of C, M, and Y with respect to the K horizontal line. (Color shift) can be detected. Further, in each color KCMY, a positional deviation in the main scanning direction of each color KCMY can be detected by obtaining the distance between the horizontal line and the diagonal line of the “F” -shaped mark. Further, in each color KCMY, by detecting the difference between the horizontal line in the main scanning direction and the left side in the main scanning direction with respect to the distance between the horizontal line and the diagonal line of the “F” -shaped mark, a magnification shift in the main scanning direction of each color KCMY is detected. can do.

  In the image forming apparatus 100 in which the first registration adjustment is completed and an image can be formed, the control unit 101 waits for a print execution instruction from the operation display unit 103 or an external device (in FIG. 3). Step S103). When a print execution instruction is issued from the operation display unit 103 or an external device (YES in step S1023 in FIG. 3), the control unit 101 instructs the image processing unit 140 and the image forming unit 150 based on image data in the image area. An instruction to print an image is given (step S104 in FIG. 3).

  Here, the control unit 101 refers to the measurement result of the in-machine temperature in the image forming unit 150 and checks whether or not a predetermined temperature (for example, ± 3 ° C.) has changed since the previous measurement. If there is a change in temperature (YES in step S105 in FIG. 3), the currently executed print (operation for forming an image in the image area based on the image data) is temporarily suspended (in FIG. 3). In step S106, the image forming unit 150 is controlled so that the adjustment-only pattern (FIG. 5A) is printed and the first resist adjustment is performed as the temporal adjustment (step S107 in FIG. 3).

  In this case, the image forming unit 150 causes various types of misregistration that may cause color misregistration, that is, misregistration in the main scanning direction, misregistration in the sub-scanning direction, inclination, and magnification deviation due to the temperature rise in the apparatus. May occur. Therefore, in order to detect various types of misregistration that can cause color misregistration in each color, that is, main-scanning direction positional deviation, sub-scanning direction positional deviation, inclination, and magnification deviation, the adjustment-dedicated pattern shown in FIG. Use to adjust the time. In the case of this first registration adjustment, it is necessary to print and read several to several tens of patterns in terms of normal paper in the sub-scanning direction. The pattern cannot be printed, and the currently executed image print is suspended.

Note that if there is an unexecuted image print at the time when the temporal adjustment is completed (not completed in step S116 in FIG. 3), the image print is resumed (step S104 in FIG. 3).
On the other hand, when the image forming unit 150 does not change the internal temperature beyond the predetermined temperature and adjustment with time is not necessary (NO in step S105 in FIG. 3), the control unit 101 is processed by the image processing unit 140. The use amount of each color toner is confirmed with reference to the image data (step S108 in FIG. 3). Here, when the image printing operation in a state where the toner usage amount is smaller than a predetermined reference is continued, the toner in the developing units 154Y to 154K is excessively charged, and as a result, the development density unevenness is likely to occur.

  Therefore, when the image printing operation in a state where the toner usage amount is small continues, a specific pattern called a discard band (FIG. 5B) is printed between the images, and the usage amount is increased in the developing units 154Y to 154K. The control unit 101 determines to discard the small toner (YES in step S109 in FIG. 3).

  At this time, the control unit 101 calculates the color of the toner to be discarded (necessary color to be discarded) and the amount of toner to be discarded (necessary amount of disposal) with reference to the usage amount of each color toner. Then, the color and area constituting the specific pattern are determined from the discard required color and the discard required amount (step S110 in FIG. 3). Based on the above determination, the control unit 101 controls the image forming unit 150 to print a specific pattern between images in accordance with the formation of an image corresponding to the image data in the image area (in FIG. 3). Step S111).

  In other words, the control unit 101 selects the toner of the color that needs to be discarded as the discharge color material according to the use state of the toner, forms a specific pattern using the discharge color material, and discharges the discharge color material. Has a color material discharge function. In this case, a specific pattern is transferred from the image carrier 151Y to 151K onto the intermediate transfer member 157 by the discharged color material (toner of a color that needs to be discarded), and is not transferred to a sheet or the like, and is discharged by a cleaning unit (not shown). Recover.

  As this specific pattern, as shown in FIGS. 5 (b) to 5 (d), a color that is not transferred to a sheet (non-transfer area) between adjacent image areas G1 to G5 is used as a color that needs to be discarded. A band pattern Pb in the main scanning direction is printed for the determined color. Note that the specific pattern (FIG. 5B) is printed between the images between the image areas, and therefore has no effect on the image print being executed.

  5 (b) to 5 (d) show cases where all four colors of YMCK are determined to be discarded, but only one color, only two colors, depending on the amount of toner used, In some cases, only three colors may be determined as discarding colors. Further, in FIG. 5B, a belt-like pattern continuous in the main scanning direction is provided for each color, but depending on the amount of disposal required, as shown in FIGS. 5C to 5D, sensors 160s1, The patterns Pb1 and Pb2 separated in two in the main scanning direction may be configured to cover the main scanning position detected in 160s2. Although not shown, the control unit 101 combines the bands Pb and the separated patterns Pb1 and Pb2 in FIGS. 5B to 5D according to the difference in the amount of disposal required for each color. The pattern may be configured as

  In this embodiment, a specific pattern between images for toner disposal is used, and registration adjustment related to a sub-scanning direction position is performed based on a sub-scanning direction position between a plurality of colors in the specific pattern. That is, a simple registration adjustment (second registration adjustment) corresponding to inspection items smaller than the first registration adjustment is performed between images during image formation by using a specific pattern for toner disposal. Color registration adjustment can be executed without stopping the image forming operation.

  Hereinafter, with reference to the flowchart of FIG. 4, in order to realize the present embodiment, a process (step S <b> 110 in FIG. 3) that determines a color and an area constituting a specific pattern from the discard required color and the discard required amount. The subroutine will be described. FIG. 6 is a table showing the relationship between the discharged color material and the added color material for each number of colors, and the reference color at the time of measurement.

  The control unit 101 selects the determined toner of the necessary color to be discarded as the discharged color material (step S1101 in FIG. 4). Then, the control unit 101 selects the discharged color material as the second pattern forming color material (step S1102 in FIG. 4). Also, the pattern area of each color (see FIGS. 5B to 5D) is determined from the required amount of disposal calculated for the discharged color material (step S1103 in FIG. 4).

Then, the control unit 101 confirms whether or not the selected discharge color material is one color (step S1104 in FIG. 4).
Here, if there are two or more colors that need to be discarded as the specific pattern for discarding the toner (NO in step S1104 in FIG. 4), the resist relating to the position in the sub-scanning direction depends on the position in the sub-scanning direction between a plurality of colors in the specific pattern. Adjustments can be performed. In this case, as shown in the table of FIG. 6, when K is included, K is determined as a measurement reference. If K is not included, the color located closest to K in the image forming unit 150 is selected as the reference color material with high priority. Then, the processing of this subroutine is finished and the processing returns to the processing of the main routine of FIG. 3 (return in FIG. 4).

  On the other hand, there is a case where only one color is required as a specific pattern for discarding toner. In such a case, the registration adjustment relating to the sub-scanning direction position cannot be executed by the sub-scanning direction position between a plurality of colors in the specific pattern. Therefore, if there is only one color that needs to be discarded as a specific pattern for toner disposal (YES in step S1104 in FIG. 4), the control unit 101 prioritizes one of the color materials that do not require disposal. The color material according to the order is added to the second pattern formation color material (step S1105 in FIG. 4).

  FIG. 6 is a table showing the relationship between the discharged color material and the added color material for each number of colors, and the reference color at the time of measurement. Here, when the discharge color material is only the K1 color, C, which is a color located closest to K in the image forming unit 150, is selected as the additional color material. In this case, a position close to K is a high priority. When the discharged color material is only one color other than K, K is selected as the additional color material. One discharged color material and one additional color material become the second pattern forming color material. Further, when the discharged color material has two or more colors, it becomes the second pattern forming color material as it is. In either case, K, which is the most visible and highly conspicuous as an image, is selected as the reference color (see the underline in FIG. 6).

  In addition, since the control unit 101 originally added the color material added to the second pattern forming color material is a color that does not need to be discarded, the control unit 101 can minimize the registration adjustment at the position in the sub-scanning direction. A pattern shape having a pattern area is determined (step S1106 in FIG. 4). Then, the processing of this subroutine is terminated, and the processing returns to the processing of the main routine of FIG. 3 (return in FIG. 4).

  FIG. 7 shows a specific example of a specific pattern formed between images on the intermediate transfer member 157. When the discharged color material is only K1 color, C, which is a color located closest to K in the image forming unit 150, is selected as the additional color material. The additional color material has a minimum pattern area that allows measurement of registration adjustment in the sub-scanning direction position (see FIG. 7A). When the discharged color material is only one color other than K, K is selected as the additional color material. The additional color material has a minimum pattern area that can be measured for registration adjustment at the position in the sub-scanning direction (see FIG. 7B). Further, when the discharged color material has two colors, a specific pattern is formed with the two colors (see FIGS. 7C and 7D). Further, when the discharged color material has three colors, a specific pattern is formed with the three colors (see FIGS. 7E and 7F). When the discharged color material has four colors, a specific pattern is formed with the four colors (see FIGS. 5B to 5D).

When the specific pattern is printed between the images of the intermediate transfer member 157 as described above, the control unit 101 detects the deviation of each pattern based on the detection results of the sensors 160s1 and 160s2 (step S112 in FIG. 3). .
Hereinafter, with reference to FIG. 8, detection of deviation in the second resist adjustment using the specific pattern will be described.

  FIG. 8A shows a specific pattern composed of four colors. In this case, the time Dkc from the timing at which the K pattern is detected to the timing at which the C pattern is detected is an estimated time calculated from the original distance between the K and C patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dkc_std. Similarly, the estimated time Dkm from the timing when the K pattern is detected to the timing when the M pattern is detected is calculated from the original distance between the K and M patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dkm_std. Similarly, the estimated time Dky from the timing when the K pattern is detected to the timing when the Y pattern is detected is calculated from the original distance between the K and Y patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dky_std.

  FIG. 8B shows a specific pattern composed of two colors. In this case, the estimated time Dcm from the timing when the C pattern is detected to the timing when the M pattern is detected is calculated from the original distance between the C and M patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dcm_std. The other two colors are detected in the same manner.

  FIG. 8C shows a specific pattern in which the color that needs to be discarded is one color and is composed of two colors together with the additional color material. In this case, the estimated time Dkm from the timing when the K pattern is detected to the timing when the M pattern is detected is calculated from the original distance between the K and M patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dkm_std. Other colors are detected in the same manner.

  In the detection of deviation using the specific pattern as described above (steps S111 to S112 in FIG. 3), if no deviation is detected (NO in step S113 in FIG. 3), the control unit 101 detects deviation due to the second resist adjustment. If correction is not performed and an unexecuted image print exists (not completed in step S116 in FIG. 3), the next image print is executed (step S104 in FIG. 3).

  On the other hand, in the case of deviation detection using the specific pattern as described above (steps S111 to S112 in FIG. 3), if a deviation is detected (YES in step S113 in FIG. 3), the control unit 101 performs the above identification. A deviation in the pattern is obtained, and correction data for eliminating the deviation is calculated (step S114 in FIG. 3).

  Here, when the specific pattern is composed of all four colors as shown in FIGS. 5B to 5D, it is desirable to calculate the deviation and the correction data for each color. On the other hand, when the specific pattern is composed of three or less colors as shown in FIGS. 7A to 7F, the specific pattern is referred to by referring to the color correction data existing in the specific pattern. It is desirable to predict and calculate correction data for nonexistent colors. Note that various known methods can be used for the prediction method.

Then, the control unit 101 sets the image processing unit 140 and the image forming unit so that the correction data is applied to the image data to be printed next and the specific pattern within a range in which the above processing such as calculation of correction data is in time. 150 is controlled (step S115 in FIG. 3).
If there is an unexecuted image print (uncompleted in step S116 in FIG. 3), the control unit 101 further executes the next image print (step S104 in FIG. 3). The processing of each step described in the above is repeatedly executed.

  In addition, the control unit 101 is in a state where there is no unexecuted image print, but a shift is detected with the above specific pattern (YES in step S113 in FIG. 3), and the image print is output with the shift still occurring. 3 (there is a misprint in step S116 in FIG. 3), the image processing unit 140 and the image forming unit 150 are controlled to reprint the misprinted image print with the correction data applied (see FIG. 3). Step S117 in FIG. 3). Further, in this case, the control unit 101 controls the operation display unit 103 to display the presence of the image print in which the shift has occurred and the presence of the reprint in a state in which the shift has been eliminated together with the number of pages.

  Further, when there is no unexecuted image print and the image print in which the shift has occurred is not output (completed in step S116 in FIG. 3), the control unit 101 completes the series of prints described above. The image processing unit 140 and the image forming unit 150 are controlled to end the processing. In this case, the control unit 101 controls the operation display unit 103 to display completion of printing.

  In the first embodiment described above, the case of two registration sensors 160s1 and 160s2 is taken as a specific example, but three or more registration sensors can be arranged. When the number of registration sensors is increased in this way, a pattern may be formed at a corresponding position in the main scanning direction to detect misalignment and calculate correction data.

[Operation (2) of the embodiment]
The operation of the image forming apparatus as the second embodiment and an image formation control program for controlling the image forming apparatus will be described below with reference to the explanatory diagram of FIG.
In FIG. 9, the intermediate transfer member 157 on which an image or pattern is formed is schematically shown together with the sensors 160s1 and 160s2.

  In the second embodiment, it is assumed that the image forming apparatus 100 uses long paper that is roll-fed. In this case, in the intermediate transfer body 157, in the entire image formable area in the main scanning direction, the area excluding both ends in the main scanning direction is an image forming area where the image is transferred to the long paper, and the main scanning direction Both end portions of the sheet are non-transfer areas where images are not transferred onto long paper.

Further, here, the registration sensors 160s1 and 160s2 are arranged at positions corresponding to the non-transfer areas in the main scanning direction.
When the image printing operation with a small amount of toner used continues, specific patterns Pb1 and Pb2 called discard bands are printed in the non-transfer area, and toner with a small amount of use is developed in the developing units 154Y to 154K. The control unit 101 controls so as to discard.

In this case, as already described in the first embodiment, the control unit 101 selects the toner of the color that needs to be discarded as the discharge color material according to the toner usage status, and uses the discharge color material to specify the specific pattern. And the discharged color material is discharged.
Here, when the discharged color material has two or more colors, it becomes the second pattern forming color material as it is.
On the other hand, in this case, as already described in the first embodiment, when the discharge color material is only K1 color, the control unit 101 selects it as an additional color material, and adds one discharge color material and one additional color material. The color material is the second pattern forming color material.

When the specific pattern is printed in the non-transfer area as described above, the control unit 101 detects the deviation of each pattern based on the detection results of the sensors 160s1 and 160s2.
FIG. 9 shows a specific pattern composed of four colors. In this case, a time Dkc from the timing when the K pattern is detected to the timing when the C pattern is detected is an expected time Dkc_std calculated from the original distance between the K and C patterns and the moving time of the intermediate transfer member 157. Is detected. Similarly, the estimated time Dkm from the timing when the K pattern is detected to the timing when the M pattern is detected is calculated from the original distance between the K and M patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dkm_std. Similarly, the estimated time Dky from the timing when the K pattern is detected to the timing when the Y pattern is detected is calculated from the original distance between the K and Y patterns and the moving time of the intermediate transfer member 157. It is detected whether or not it matches Dky_std.

In addition, although the case where the specific pattern is configured with four colors is shown here, the control unit 101 is similar to the description of the first embodiment described above even when the discard-necessary colors are one to three colors. The shape and area of the second pattern forming color material are determined.
Similarly to the first embodiment, when the specific pattern is composed of all four colors, it is desirable to calculate the deviation and the correction data for each color. On the other hand, when the specific pattern is composed of three or less colors, the correction data of the color not existing in the specific pattern is predicted and calculated with reference to the correction data of the color existing in the specific pattern.

In the second embodiment, when the power of the image forming apparatus 100 is turned on, the control unit 101 prints an adjustment-dedicated pattern (see FIG. 5A), and the first of all four colors in the main scanning direction and the sub-scanning direction. The image forming unit 150 is controlled to execute registration adjustment as power-on adjustment.
After starting the image formation using the long paper, a specific pattern that combines toner disposal and simple second resist adjustment is formed in the non-transfer area of the intermediate transfer body 157, and only in the sub-scanning direction. Perform resist adjustment.

Note that the main cause of color registration misalignment during continuous printing using long paper is the speed fluctuation of the intermediate transfer member 157 due to thermal expansion of the intermediate transfer unit 155.
For this reason, it is possible to ensure the necessary color resist accuracy even by simple second resist adjustment only in the sub-scanning direction.

In addition, when the specific pattern for the second resist adjustment also used for toner disposal can be formed in the non-transfer area of the intermediate transfer member 157, the toner can be discarded during continuous printing on a roll-fed long paper. It is possible to eliminate the continuous print distance limitation in which deterioration is rate limiting.
When the specific pattern of the second resist adjustment is formed in the non-transfer area of the intermediate transfer body 157, when the normal installation position of the registration sensor 160 is within the image area, the registration sensor 160 is moved to the normal installation position. You may make it move from (inside an image area) to a non-transfer area. In this case, the moving means of the registration sensor 160 may be either automatic or manual.

  In addition, as described above, the formation of the specific pattern in the non-transfer area and the reading by the registration sensor 160 can be applied to the registration adjustment between images of a normal standard size paper that is not a long paper. .

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Control part 102 Communication part 103 Operation display part 104 Memory | storage part 105 Paper feeding part 110 Conveyance part 120 Original reading part 130 Image data storage part 140 Image processing part 150 Image forming part 160 Registration sensor

Claims (10)

An image forming unit that forms an image by transferring an image formed on an image carrier using a plurality of different color materials to paper;
A sensor for detecting the color material in the image forming unit;
A control unit that controls image formation by the image forming unit;
An image forming apparatus comprising:
The controller is
According to the use situation of each color of the color material, a low-use color material is selected as the discharge color material, a specific pattern is formed on the image carrier using the discharge color material, and the discharge color material It has a color material discharge function to discharge
The specific pattern is formed by any one of the plurality of color materials of the discharge color materials or the non-discharge color material that is not selected by the color material discharge function and the discharge color material,
Controlling the image forming unit to perform registration adjustment according to a detection result of positions between the color materials in the specific pattern;
An image forming apparatus. The control unit determines a color material serving as a reference for the resist adjustment among the plurality of color materials included in the specific pattern according to a predetermined priority order.
The image forming apparatus according to claim 1. The control unit determines a color material to be a reference in the registration adjustment according to a priority order according to the arrangement of the image carrier in the image forming unit.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. In the case where the specific pattern is formed by the discharge color material and the non-discharge color material, the control unit has a smaller area of the specific pattern by the non-discharge color material than the specific pattern by the discharge color material. To control,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit refers to the measurement result of the resist adjustment in the color material on which the specific pattern is formed, calculates correction data for the color material that does not form the specific pattern, and applies the resist adjustment.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit is configured such that the specific pattern by the discharged color material has a shape or an area according to a discharge amount required by the color material discharge function.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit controls the image forming unit to discharge the discharged color material and perform the registration adjustment without interrupting an image forming operation being performed.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The controller is
As the registration adjustment, a first registration adjustment is performed based on an adjustment-dedicated pattern corresponding to a plurality of inspection items, and a first adjustment is performed based on the specific pattern corresponding to inspection items smaller than the first registration adjustment. 2 It has a function to select and execute either of the resist adjustment,
Discharging the discharged color material by forming the specific pattern on the image carrier and controlling the image forming unit to perform the second resist adjustment;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. When the rotation direction of the image carrier is a sub-scanning direction, and the direction perpendicular to the sub-scanning direction on the surface of the image carrier is a main scanning direction,
The control unit controls the image forming unit to perform the first registration adjustment that detects a positional deviation in the main scanning direction, a positional deviation in the sub-scanning direction, a tilt, and a magnification deviation using the adjustment-dedicated pattern, Using the specific pattern, the image forming unit is controlled to perform the second registration adjustment for detecting a positional deviation and a tilt in the sub-scanning direction.
The image forming apparatus according to claim 8. An image forming unit that forms an image by transferring an image formed on an image carrier using a plurality of color materials onto paper;
According to the use situation of each color of the color material, a low-use color material is selected as the discharge color material, a specific pattern is formed on the image carrier using the discharge color material, and the discharge color material The specific pattern is formed by any one of the plurality of color materials, the non-discharge color material that is not selected by the color material discharge function or the color material discharge function. A control unit configured to control the image forming unit to perform registration adjustment according to a detection result of positions between the plurality of color materials in the specific pattern;
As an image forming control program for causing a computer of an image forming apparatus to function.