JP2008216395A - Image forming apparatus and image forming method - Google Patents

Abstract

To provide an image forming apparatus that performs density gradation correction in a short time with a small and inexpensive configuration by utilizing an empty area on a transfer belt that occurs due to a small width of paper to be printed.
An image forming apparatus compares a main scanning direction size of paper to be printed with a main scanning direction size of an image carrier, and forms a test pattern in parallel with a printed image in a non-printed image area on the image carrier. A parallel formation determination means for determining whether or not it is possible, and when the parallel formation determination means determines that a test pattern can be formed in parallel with the print image, a test pattern is formed in the non-image area in parallel with the print image; Then correct the image forming conditions.
[Selection] Figure 1

Description

  The present invention relates to an image forming apparatus and an image forming method for an electrophotographic double-sided image.

  Printers using an electrophotographic system, such as a laser printer, change the image quality when environmental changes in temperature and humidity, changes over time, etc., so a test pattern is formed on the intermediate transfer belt at a predetermined timing, and the sensor It is known that density gradation correction is automatically performed by reading a test pattern.

  When density gradation correction is performed during printing, it is necessary to interrupt printing until the test pattern is read from the sensor after the test pattern is formed and the test pattern is cleaned from the intermediate transfer belt. There was a problem that decreased.

As a conventional method for this problem, a plurality of sensors are prepared on the intermediate transfer belt, and a test pattern is formed in parallel (see Patent Document 1), or a region for forming a test pattern on the intermediate transfer belt is secured in advance. A method for forming a test pattern at both ends of a printed image, a method for forming a test pattern between printed images, and the like have been proposed.
JP 2006-139179 A

  However, these methods have the following problems. A plurality of sensors are required, which increases the cost.

  In addition, the printer becomes larger. Furthermore, the intervals between the print images are limited by a certain interval determined by productivity (the number of print images output in a predetermined time) and process speed (rotational speed of the photosensitive member or intermediate transfer belt for developing the toner image). In addition, since a sampling time by the sensor is also required between the limited print images, many test patterns cannot be formed in the paper feed direction.

  Therefore, in the present invention, in consideration of the above-described problems, density gradation correction is performed in a short time with a small and inexpensive configuration by using an empty area on the transfer belt that is generated due to a small width of paper to be printed. An object of the present invention is to provide an image forming apparatus.

  The invention described in claim 1 is a print data receiving means for receiving print data, a print image forming means for forming a print image on the image carrier, and a test pattern forming means for forming a plurality of test patterns on the image carrier. In the image forming apparatus having a detecting means for reading a test pattern and an image forming condition correcting means for correcting an image forming condition based on a detection result detected by the detecting means, the main scanning direction size of the paper to be printed and the image Parallel formation determination means for comparing the size in the main scanning direction of the carrier and determining whether or not a test pattern can be formed in parallel with the print image in the non-printed image area on the image carrier, When it is determined that the test pattern can be formed in parallel with the print image, the test pattern is formed in the non-image area in parallel with the print image to correct the image forming condition. An image forming apparatus.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, when the parallel formation determining unit determines that a test pattern can be formed in parallel with the print image, the test is performed in a non-image area in parallel with the print image. The apparatus further includes a selection unit that allows a user to select whether or not to form a pattern.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, an environmental change detecting means for detecting an environmental change that affects print image formation, such as a change in temperature / humidity or a change with time, and an environmental change detection And a first correction determination unit that determines whether or not image formation condition correction is desirable from the environmental change detection result detected by the unit, and when the first correction determination unit determines that image formation condition correction is desirable, printing is performed. It is characterized in that it is determined whether or not a test pattern can be formed in parallel with a print image when data is received.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the second correction determination unit further determines whether or not the image forming condition correction is necessary immediately from the environmental change detection result detected by the environmental change detection unit. And when the second correction determining unit determines that the image forming condition correction is necessary immediately, the printing is interrupted and the image forming condition correction is performed.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, the paper accumulation unit capable of accumulating a plurality of sizes of paper and the parallel formation determination unit do not form a test pattern in parallel with the print image. A substitute print determining means for determining whether or not a test pattern can be formed in parallel with the print image by printing in place of the paper stored in the paper storage means when it is determined to be possible; In addition, when the substitute printing determining means prints on the substitute paper and determines that the test pattern can be formed in parallel with the print image, the test pattern is formed in parallel with the print image, and the print image is substituted for the substitute paper. It is characterized by printing.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, when continuous printing is performed on a paper on which a test pattern can be formed in parallel with the print image, the last print image It further comprises first test pattern position adjusting means for forming a test pattern in parallel.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, when the test pattern cannot be formed in parallel with the print image, the in-machine contamination due to the test pattern after the print image has passed the transfer position to the paper. It is further characterized by further comprising a cleaning means for reducing the above.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth and seventh aspects, when continuous printing is performed on a paper on which a test pattern can be formed in parallel with the print image, the last printing is performed. The image forming apparatus further includes second test pattern position adjusting means for forming a test pattern so that the rear end of the image matches the rear end of the test pattern.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the first aspect, a print data receiving step for receiving print data, a print image forming step for forming a print image on an image carrier, and a plurality of test patterns. In an image forming method comprising: a test pattern forming step formed on a carrier; a detection step of reading a test pattern; and an image forming condition correction step of correcting an image forming condition based on a detection result detected in the detection step. Parallel formation that compares the main scanning direction size of the paper to be printed with the main scanning direction size of the image carrier and determines whether a test pattern can be formed in parallel with the print image in the non-printed image area on the image carrier If the parallel formation determination step determines that a test pattern can be formed in parallel with the print image, a test pattern is formed in the non-image area in parallel with the print image. The image forming method which is characterized in that the image forming conditions corrected.

  According to a tenth aspect of the present invention, in the image forming method according to the ninth aspect, when the parallel formation determining step determines that a test pattern can be formed in parallel with the print image, the test is performed on the non-image area in parallel with the print image. The method further includes a selection step in which a user can select whether or not to form a pattern.

  According to an eleventh aspect of the present invention, in the image forming method according to the tenth aspect, an environmental change detecting step for detecting an environmental change that affects print image formation such as a change in temperature and humidity and a change with time, and an environmental change detecting step are detected A first correction determination step for determining whether or not image formation condition correction is desirable from the environmental change detection result, and when the first correction determination step determines that image formation condition correction is desirable, print data is received. It is sometimes judged whether or not a test pattern can be formed in parallel with the print image.

  According to a twelfth aspect of the present invention, in the image forming method according to the eleventh aspect, the second correction determination step of determining whether or not the image forming condition correction is necessary immediately from the environmental change detection result detected by the environmental change detection step. And when the second correction determination step determines that the image forming condition correction is necessary immediately, the printing is interrupted and the image forming condition correction is performed.

  According to a thirteenth aspect of the present invention, in the image forming method according to the eleventh or twelfth aspect, the paper accumulation step capable of accumulating a plurality of sizes of paper and the parallel formation judgment step cannot form a test pattern in parallel with the print image. A substitute print determination step for determining whether or not a test pattern can be formed in parallel with the print image by printing in place of the paper stored in the paper storage step when it is determined that it is possible. In addition, if it is determined that the test pattern can be formed in parallel with the print image by printing on the substitute paper in the substitute print determination step, the test pattern is formed in parallel with the print image, and the print image is substituted. It is characterized by printing on paper.

  According to a fourteenth aspect of the present invention, in the image forming method according to any one of the ninth to thirteenth aspects, when continuous printing is performed on a paper on which a test pattern can be formed in parallel with the printed image, the last printed image The method further includes a first test pattern position adjusting step of forming a test pattern in parallel.

  According to a fifteenth aspect of the present invention, in the image forming method according to the fourteenth aspect, if the test pattern cannot be formed in parallel with the print image, the in-machine contamination due to the test pattern after the print image passes the transfer position to the paper. It further has a cleaning process for reducing the above.

  The invention according to claim 16 is the image forming method according to any one of claims 9 to 13 and 15, wherein the last printing is performed when the test pattern can be continuously printed in parallel with the print image. The method further includes a second test pattern position adjusting step for forming the test pattern so that the rear end of the image and the rear end of the test pattern coincide with each other.

  According to the present invention, there is provided an image forming apparatus that performs density gradation correction in a short time with a small and inexpensive configuration by using an empty area on a transfer belt that is generated due to a small width of paper to be printed. Can do.

  First, a basic configuration of an image forming apparatus as an embodiment according to the present invention will be described.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. Each color AIO cartridge (106Bk, 106M, 106C, 106Y) is arranged along the transfer belt 105, which is a so-called tandem type. The transfer belt 105 rotates counterclockwise in FIG. 1, and a plurality of AIO cartridges (electrophotographic process units) 106Bk, 106M, 106C, and 106Y are arranged in order from the upstream side in the rotation direction. The plurality of AIO cartridges 106Bk, 106M, 106C, and 106Y have the same internal configuration except that the color of the toner image to be formed is different. The AIO cartridge 106Bk forms a black image, the AIO cartridge 106M forms a magenta image, the AIO cartridge 106C forms a cyan image, and the AIO cartridge 106Y forms a yellow image.

  In the following description, the AIO cartridge 106Bk will be described in detail. However, since the other AIO cartridges 106M, 106C, and 106Y are the same as the AIO cartridge 106Bk, the components of the image forming units 106M, 106C, and 106Y are described. Instead of Bk attached to each component of the image forming apparatus 106Bk, only the symbols distinguished by M, C, and Y are displayed in the figure, and the description is omitted.

  The transfer belt 105 is an endless belt wound around a secondary transfer driving roller 107 and a transfer belt tension roller 108 that are rotationally driven. The secondary transfer drive roller 107 is driven to rotate by a drive motor (not shown), and the drive motor, the secondary transfer drive roller 107, and the transfer belt tension roller 108 serve as drive means for moving the transfer belt 105. Function.

  The image forming unit 106Bk includes a photoconductor 109Bk as a photoconductor, a charger 110Bk arranged around the photoconductor 109Bk, an exposure device 111, a developing device 112Bk, a cleaner blade 113Bk, and the like. The exposure device 111 is configured to irradiate laser beams 114Bk, 114M, 114C, and 114Y that are exposure lights corresponding to image colors formed by the AIO cartridges 106Bk, 106M, 106C, and 106Y.

  At the time of image formation, the outer peripheral surface of the photoconductor 109Bk is uniformly charged by the charger 110Bk in the dark and then exposed by the laser beam 114Bk corresponding to the black image from the exposure device 111 to form an electrostatic latent image. Is done. The developing device 112Bk visualizes the electrostatic latent image with black toner, thereby forming a black toner image on the photoreceptor 109Bk.

  This toner image is transferred onto the transfer belt 105 by the action of the primary transfer roller 115Bk at the position where the photoconductor 109Bk and the transfer belt 105 are in contact (primary transfer position). By this transfer, an image of black toner is formed on the transfer belt 105. After the transfer of the toner image is completed, the photosensitive member 109Bk waits for the next image formation after the unnecessary toner remaining on the outer peripheral surface is wiped off by the cleaner blade 113Bk.

  As described above, the transfer belt 105 to which the black toner image is transferred by the AIO cartridge 106Bk is conveyed to the next AIO cartridge 106M by the transfer belt 105. In the AIO cartridge 106M, a magenta toner image is formed on the photoreceptor 109M by a process similar to the image forming process in the AIO cartridge 106Bk, and the toner image is superimposed on the black image formed on the transfer belt 105. Transcribed.

  The transfer belt 105 is further conveyed to the next AIO cartridges 106C and 106Y, and a cyan toner image formed on the photoconductor 109C and a yellow toner image formed on the photoconductor 109Y are subjected to the same operation. Then, the image is transferred onto the transfer belt in a superimposed manner. Thus, a full color toner image is formed on the transfer belt 105.

  In the image formation, when only black is printed, the primary transfer roller 115M, the primary transfer roller 115C, and the primary transfer roller 115Y are retracted to positions separated from the photoconductor 109M, the photoconductor 109C, and the photoconductor 109Y, respectively. The above-described image forming process is performed only for black.

  Below the transfer belt 105, a paper feed unit having a paper feed tray 101, a paper feed roller 102, a registration roller 103, and the like is provided. Further, a secondary transfer roller 116 is provided so as to face the secondary transfer driving roller 107. Here, the secondary transfer driving roller 107 sandwiches the transfer belt 105 between the secondary transfer roller 116 and forms a secondary transfer nip. Further, a fixing device 122, a paper discharge roller 118, and the like are provided above the secondary transfer nip.

  The paper feed tray 101 stores a plurality of sheets 104 as recording media, and a paper feed roller 102 is in contact with the uppermost paper 104. The sheet feeding roller 102 is rotated by a driving unit (not shown), and temporarily stops rotating in a state where the leading end of the uppermost sheet 104 is abutted against the registration roller 103. Then, the sheet 104 is sent out toward a secondary transfer nip to which a transfer bias is applied at an appropriate timing. The toner image formed on the transfer belt 105 is transferred to the paper 104 at the secondary transfer nip. Transfer residual toner that has not been transferred to the paper 104 is attached to the transfer belt 105 after passing through the secondary transfer nip. This is cleaned by the intermediate belt cleaner.

  The toner image transferred to the surface of the sheet 104 that has passed through the secondary transfer nip is fixed by heat and pressure when passing between the rollers of the fixing device 122. Thereafter, the paper 104 is discharged out of the apparatus by a paper discharge roller 118.

  Next, the basic electrical configuration of the image forming apparatus according to the embodiment of the present invention will be described with reference to FIG. The image forming apparatus includes a CPU 10, an image memory 20, an I / O (input / output unit) 30, an I / F (interface unit) 40, a ROM 50, a RAM 60, and an operation panel 70. The CPU 10 controls each part constituting the image forming apparatus according to a program stored in the ROM 50. The image memory 20 temporarily stores image data included in the print data. The I / O 30 controls input / output of electrical components such as an image forming unit and a sensor. The I / F 40 receives print data and an inquiry response to the user from a personal computer or a server connected to the apparatus via a cable or the like. The ROM 50 stores a program for controlling the entire apparatus. The RAM 60 temporarily stores various information related to the device. The operation panel 70 is a means for the user to grasp the state of the apparatus and set operation changes of the apparatus.

  Next, details of image forming condition correction as each embodiment of the present invention will be described. In an electrophotographic image forming apparatus, the density and gradation of an image fluctuate due to environmental changes such as temperature and humidity, and deterioration with time. For this reason, it is necessary to correct image fluctuations at a predetermined timing, such as when the main power is turned on, when waiting for a predetermined time, or after printing a predetermined number of sheets or more. As a specific correction method, when a predetermined timing comes, first, the photosensitive members 109Y, 109C, 109M, and 109K are uniformly charged while rotating. Then, laser light 114Y, 114C, 114M, and 114Bk is irradiated while gradually increasing the output power to form an electrostatic latent image for a test pattern. The electrostatic latent image is developed by the developing devices 112Y, 112C, 112M, and 112Bk, and a test pattern is formed on the transfer belt 105. FIG. 3 shows a test pattern formed on the transfer belt 105. Seven patches having different color densities are formed. The amount of reflection of the test pattern is detected when it passes through a position facing the reflective photosensor 117 as the transfer belt 105 moves endlessly. The detected reflection amount is converted into toner adhesion amount and accumulated as density pattern data of each color. Next, an approximate expression of the laser power and the toner adhesion amount is calculated from the density pattern data. Finally, the laser power for obtaining the target toner adhesion amount is determined from the approximate expression and set as the corrected image forming condition. The test pattern that has passed through the position facing the photosensor 117 is cleaned by the intermediate transfer belt cleaner.

  (Embodiment 1) Next, Embodiment 1 corresponding to claims 1 to 4 and 9 to 12 will be described with reference to FIGS.

  FIG. 6 shows a flowchart. First, print data is input to the configuration via the I / F, the print data is expanded in the RAM, and the image data is expanded in the image memory. Next, whether or not the image forming condition correction is necessary immediately is determined based on whether or not the number of printed sheets from the previous image forming condition correction is 200 or less in this embodiment. If the number of printed sheets exceeds 200, printing is interrupted, image forming condition correction is performed, and the number of printed sheets is reset. If the number of printed sheets is 200 or less, it is determined whether the user is set to form a test pattern in the non-image area in parallel with the printed image. If there is a user setting, it is subsequently determined whether or not image forming condition correction is desirable. In this embodiment, whether or not the number of printed sheets from the previous image forming condition correction is 170 or less is determined as a reference. If the number of printed sheets exceeds 170, it is subsequently determined whether or not a test pattern can be formed in parallel with the printed image. In this embodiment, the width of the sheet to be printed (size in the main scanning direction) is 210 mm. Judgment is based on the following. When the print paper width is 210 mm or less, a test pattern is formed in parallel with the print image, and image forming condition correction is performed. Finally, the number of prints is reset and the process ends. If there is no user setting, or the number of printed sheets is 170 or less or the printing paper width exceeds 210 mm, one printed image is formed in the same manner as normal printing, and the number of printed sheets is counted up. If the next print image still exists in the print data, the process returns to the determination of whether or not the image forming condition correction is necessary immediately, and ends if the next print image does not exist in the print data.

  FIGS. 4 and 5 show how test patterns are formed in parallel with the print image on the transfer belts of the A3 central transporter and the A3 one-side transporter, respectively. In the case of a one-side transporter, it is possible to increase the criterion for determining whether or not a test pattern can be formed in parallel with the print image, compared to the central transporter. For the A4 machine (not shown), the criterion is a postcard size or the like. In the configuration shown here, a total of three photosensors are installed on the left, right, and center. This is because it is necessary when correcting color misregistration that is not handled in the present invention. In the density gradation correction handled in the present invention, only one photosensor is required. In addition, the reason why the test patterns are formed in a row here is to suppress the number of expensive photosensors to one. In order to calculate the color toner adhesion amount, a regular reflection amount and a diffuse reflection amount are required. Therefore, an expensive photosensor is required to measure a test pattern in density gradation correction.

  (Embodiment 2) Next, Embodiment 2 corresponding to claims 5 and 13 will be described with reference to FIG. In this embodiment, a sheet substitution process is added to the configuration of the first embodiment, and the flowchart of FIG. 7 is based on the processing procedure of the flowchart of FIG.

  When the print paper width exceeds 210 mm, it is determined whether the paper feed unit for the print paper can be changed. When it is determined that the change is possible, the paper feed unit is changed for printing. For example, when there is a first paper feed unit set to convey A4 paper in a lateral feed and a second paper feed unit set to carry A4 paper in a vertical feed, for example. Normally, when print data for A4 paper is received, paper is fed from the first paper feed unit, but intentionally fed from the second paper feed unit and printed. If it is determined that the paper feed unit cannot be changed, the process proceeds to a process of forming one print image as in normal printing.

  (Embodiment 3) Next, Embodiment 3 corresponding to claims 6 to 7 and 14 to 15 will be described with reference to FIG. In the present embodiment, the test pattern formation timing of the configuration of the second embodiment is changed and a cleaning process is added. The flowchart of FIG. 8 is based on the processing procedure of the flowchart of FIG. To do.

  When the print paper width is 210 mm or less or when the paper feed unit is changed, it is determined whether there is a next print image. If it is determined that there is a next print image, the process proceeds to a process of forming one print image as in normal printing. If it is determined that there is no next print image, a test pattern is formed in parallel with the print image, and the reflection amount is detected by the photosensor. Next, the process waits until the print image passes through the secondary transfer nip. When the print image has already passed through the secondary transfer nip, a cleaning bias is applied. Here, the cleaning bias is a bias that acts to prevent the toner image from separating from the transfer belt at the secondary transfer nip, contrary to the transfer bias. After applying the cleaning bias, the toner adhesion amount is converted from the data detected by the photosensor, and the optimum laser power is set from the approximate expression. Finally, the number of prints is reset and the process ends.

  (Embodiment 4) Next, Embodiment 4 corresponding to claims 8 and 16 will be described with reference to FIG. In the present embodiment, the print image and test pattern formation processing of the configuration of the third embodiment is changed, and the flowchart of FIG. 9 is based on the processing procedure of the flowchart of FIG.

  When the printing paper width is 210 mm or less or when the paper feeding unit is changed, it is determined whether the remaining printing distance is less than the total distance of the test pattern. Here, the remaining printing distance is the sum of the sub-scanning distance and the printing image interval of the printing image formed until printing of the received printing data is completed. In this example, the total distance of the test pattern was 638 mm shown in FIG. When the remaining printing distance exceeds 638 mm, one line of the printed image is formed in the main scanning direction, and the process returns to determining whether the remaining printing distance is equal to or less than the total distance of the test pattern. When the remaining printing distance is 638 mm or less, the process of forming one line of the test pattern in the main scanning direction in parallel with the print image is repeated until the formation of all the print images is completed. Next, it is determined whether or not the test pattern formation is completed. If the test pattern has been formed, the laser power is set and the number of printed sheets is reset. If the formation of the test pattern is not completed, the remaining test pattern is formed, and the cleaning process and the laser power are set as in the third embodiment.

The purpose and effect of each claim will be described below.
(Claim 2) <Problem> In the image forming apparatus according to claim 1, the user's intention cannot be reflected and the operability is poor. <Purpose> The present invention provides an image forming apparatus with high operability capable of reflecting the user's intention.

  (Claim 3) (Claim 4) <Problem> In the image forming apparatus according to claims 1 and 2, the execution timing of density gradation correction cannot be set. <Object> The present invention provides an image forming apparatus capable of performing density gradation correction at an appropriate timing by detecting an environmental change.

  (Claim 5) <Problem> In the image forming apparatus according to claims 3 to 4, there are many situations in which printing is interrupted and density gradation correction is performed. <Purpose> The present invention provides an image forming apparatus in which the probability of occurrence of printing interruption is reduced by substituting printing paper with other paper.

  (Claim 6) <Problem> In the image forming apparatus according to any one of claims 1 to 5, the interior of the apparatus is contaminated by the rotation of the secondary transfer roller to which the test pattern toner is adhered. <Object> The present invention provides an image forming apparatus that reduces the amount of toner adhering to a secondary transfer roller dispersed in the apparatus by delaying the test pattern formation timing.

  (Claim 7) <Problem> In the image forming apparatus according to claim 6, the interior of the apparatus is contaminated by the rotation of the secondary transfer roller to which the test pattern toner is adhered. <Purpose> The present invention provides an image forming apparatus in which a bias is applied so that toner of a test pattern does not adhere to a secondary transfer roller, thereby reducing the amount of toner dispersed in the apparatus.

  (Claim 8) <Problem> In the image forming apparatuses according to claims 1 to 5, when the test pattern is formed even after the print image is formed, the user cannot print until the test pattern is cleaned. <Purpose> The present invention provides an image forming apparatus in which the time during which a user cannot print is shortened by starting the formation of a test pattern at a timing at which the printed image and the end of the test pattern match.

  (Claim 9) <Problem> The same as in claim 1. <Purpose> The present invention provides an image forming method in which density gradation correction is performed in a short time with a small and inexpensive configuration by utilizing an empty area on a transfer belt generated by a small width of paper to be printed. To do.

  (Claim 10) <Problem> In the image forming method of claim 9, the user's intention cannot be reflected, and the operability is poor. <Object> The present invention provides an image forming method with high operability capable of reflecting the user's intention.

  (Claim 11) (Claim 12) <Problem> In the image forming method of claims 9 to 10, the execution timing of density gradation correction cannot be set. <Object> The present invention provides an image forming method capable of performing density gradation correction at an appropriate timing by detecting an environmental change.

  (Claim 13) <Problem> In the image forming method according to any one of claims 11 to 12, there are many situations in which printing is interrupted and density gradation correction is performed. <Object> The present invention provides an image forming method in which the probability of occurrence of printing interruption is reduced by substituting printing paper with another paper.

  <Claim 14> <Problem> In the image forming method of claims 9 to 13, the interior of the apparatus is contaminated by rotation of the secondary transfer roller to which the test pattern toner is adhered. <Object> The present invention provides an image forming method in which the amount of toner adhering to a secondary transfer roller is reduced by delaying the test pattern formation timing.

  <Claim 15> <Problem> In the image forming method of claim 14, the interior of the apparatus is contaminated by rotation of the secondary transfer roller to which the test pattern toner is adhered. <Purpose> The present invention provides an image forming method in which a bias is applied so that toner of a test pattern does not adhere to a secondary transfer roller, thereby reducing the amount of toner dispersed in the apparatus.

  <Claim 16> <Problem> In the image forming method according to claims 9 to 13 and 15, when the test pattern is formed even after the print image is formed, the user cannot print until the test pattern is cleaned. <Purpose> The present invention provides an image forming method in which the time during which a user cannot print is shortened by starting the formation of a test pattern at the timing when the print image and the end of the test pattern match.

  Each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the scope of the present invention.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a diagram illustrating a basic electrical configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the test pattern formed on a transfer belt. It is a figure which shows a mode that the test pattern was formed in parallel with the printing image on the transfer belt. It is a figure which shows a mode that the test pattern was formed in parallel with the printing image on the transfer belt. It is a figure which shows the processing operation which concerns on embodiment of this invention. FIG. 10 is a diagram illustrating a processing operation according to the second embodiment. FIG. 10 is a diagram illustrating a processing operation according to the third embodiment. FIG. 10 is a diagram illustrating a processing operation according to a fourth embodiment.

Explanation of symbols

105 Transfer belt 106Bk, 106M, 106C, 106Y AIO cartridge 107 Secondary transfer drive roller 108 Transfer belt tension roller 109Bk Photoreceptor 110Bk Charger 111 Exposure unit 112Bk Developer 113Bk Cleaner blade 114Bk, 114M, 114C, 114Y Laser light 109Bk Photoreceptor

Claims (16)

Print data receiving means for receiving print data;
Print image forming means for forming a print image on an image carrier;
Test pattern forming means for forming a plurality of test patterns on the image carrier;
Detection means for reading test patterns;
An image forming condition correcting unit that corrects the image forming condition based on the detection result detected by the detecting unit;
In an image forming apparatus having
Parallel formation that compares the main scanning direction size of the paper to be printed with the main scanning direction size of the image carrier and determines whether a test pattern can be formed in parallel with the print image in the non-printed image area on the image carrier A judgment means,
Image formation characterized in that when the parallel formation determination means determines that a test pattern can be formed in parallel with the print image, the test pattern is formed in a non-image area in parallel with the print image to correct the image forming condition. apparatus.   When the parallel formation determination unit determines that the test pattern can be formed in parallel with the print image, the parallel formation determination unit further includes a selection unit that allows the user to select whether or not to form the test pattern in the non-image region in parallel with the print image. The image forming apparatus according to claim 1. Environmental change detection means for detecting environmental changes that affect print image formation, such as temperature and humidity changes and changes over time;
First correction determination means for determining whether or not image formation condition correction is desirable from the environmental change detection result detected by the environmental change detection means;
Further comprising
3. The method according to claim 1, wherein when the first correction determination unit determines that the image forming condition correction is desirable, it is determined whether or not a test pattern can be formed in parallel with the print image when the print data is received. Image forming apparatus. A second correction determination means for determining whether or not image formation condition correction is immediately necessary from the environmental change detection result detected by the environmental change detection means;
4. The image forming apparatus according to claim 3, wherein when the second correction determining unit determines that the image forming condition correction is necessary immediately, the printing is interrupted and the image forming condition correction is performed. Paper storage means capable of storing paper of a plurality of sizes;
When the parallel formation determination unit determines that the test pattern cannot be formed in parallel with the print image, the test pattern is formed in parallel with the print image by printing instead of the paper stored in the paper storage unit. Substitute printing judgment means for judging whether or not it is possible,
Further comprising
If the substitute printing determination means prints on the substitute paper and determines that a test pattern can be formed in parallel with the print image, the test pattern is formed in parallel with the print image and the print image is printed on the substitute paper. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.   2. The apparatus according to claim 1, further comprising first test pattern position adjusting means for forming a test pattern in parallel with the last printed image when continuously printing on a paper on which a test pattern can be formed in parallel with the printed image. 6. The image forming apparatus according to any one of items 1 to 5.   7. The cleaning apparatus according to claim 6, further comprising a cleaning unit that reduces in-machine contamination due to the test pattern after the print image has passed the transfer position to the paper when the test pattern cannot be formed in parallel with the print image. Image forming apparatus.   A second test pattern position adjusting means for forming a test pattern so that the trailing edge of the last printed image and the trailing edge of the test pattern coincide with each other when continuously printing on a paper on which a test pattern can be formed in parallel with the printed image; The image forming apparatus according to claim 1, further comprising: A print data receiving process for receiving print data;
A print image forming process for forming a print image on an image carrier;
A test pattern forming process for forming a plurality of test patterns on the image carrier;
A detection process for reading test patterns;
An image forming condition correcting step for correcting the image forming condition based on the detection result detected in the detecting step;
In an image forming method having
Parallel formation that compares the main scanning direction size of the paper to be printed with the main scanning direction size of the image carrier and determines whether a test pattern can be formed in parallel with the print image in the non-printed image area on the image carrier And further comprising a judgment process
If the parallel formation determination step determines that a test pattern can be formed in parallel with the print image, the image formation is performed by forming a test pattern in a non-image area in parallel with the print image and correcting the image forming condition. Method.   When the parallel formation determination step determines that the test pattern can be formed in parallel with the print image, the image forming apparatus further includes a selection step that allows the user to select whether or not to form the test pattern in the non-image area in parallel with the print image. The image forming method according to claim 9. An environmental change detection process that detects environmental changes that affect print image formation, such as temperature and humidity changes and changes over time;
A first correction determination step for determining whether image forming condition correction is desirable from the environmental change detection result detected by the environmental change detection step;
Further comprising
11. The method according to claim 9, wherein when the first correction determination step determines that the image forming condition correction is desirable, it is determined whether a test pattern can be formed in parallel with the print image when receiving the print data. Image forming method. A second correction determination step of determining whether or not image formation condition correction is immediately necessary from the environmental change detection result detected by the environmental change detection step;
12. The image forming method according to claim 11, wherein when the second correction determination step determines that the image forming condition correction is necessary immediately, the printing is interrupted and the image forming condition correction is performed. A paper accumulation process capable of accumulating multiple sizes of paper;
When the parallel formation determination process determines that a test pattern cannot be formed in parallel with the print image, the test pattern is formed in parallel with the print image by printing in place of the paper stored in the paper storage process. A substitute printing determination process for determining whether or not it is possible;
Further comprising
If it is determined that the test pattern can be formed in parallel with the print image by printing on the substitute paper in the substitute printing determination step, the test pattern is formed in parallel with the print image and the print image is printed on the substitute paper. The image forming method according to claim 11 or 12, wherein:   10. The method according to claim 9, further comprising a first test pattern position adjusting step of forming a test pattern in parallel with the last printed image when continuously printing on a paper on which a test pattern can be formed in parallel with the printed image. 14. The image forming method according to any one of items 1 to 13.   15. The method according to claim 14, further comprising a cleaning step of reducing in-machine contamination due to the test pattern after the print image passes through the transfer position to the paper when the test pattern cannot be formed in parallel with the print image. Image forming method.   When continuously printing on a paper on which a test pattern can be formed in parallel with the print image, a second test pattern position adjusting step for forming the test pattern so that the rear end of the last print image and the rear end of the test pattern coincide with each other. The image forming method according to claim 9, further comprising:

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