JP2006163380A - Image forming apparatus and image control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a means capable of enabling an operator who has difficulty in prescribing the cause of an image defect to speedily resolve the image defect. <P>SOLUTION: The image forming apparatus is provided with a recovery mode which can be started by a user and in which sticking matter on an intermediate transfer belt as an image carrier is removed and toner image formation position control and toner image formation condition control are performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an intermediate transfer member. In particular, when an image defect occurs, an image forming apparatus in which an operator of the image forming apparatus can manually perform a mode for eliminating the image defect, and the above mode is executed according to an instruction from the operator of the image forming apparatus. The present invention relates to an image forming method.

  Conventionally, a mode for eliminating an image defect may be automatically performed by an image forming apparatus based on the number of printed images or the like, or may be performed by an operator pressing a mode start switch.

  If the operator can manually execute the mode for eliminating the image defect, it is possible to cope with an image defect that occurs suddenly.

  Patent Document 1 discloses an image forming apparatus having a cleaning mode for removing an external additive of a developer attached to an intermediate transfer member, which can be executed by an operator instructing from an operation panel of the image forming apparatus. ing.

In this image forming apparatus, when an operator finds a so-called ghosted image defect in which a trace of a previously formed image appears in the next image, cleaning is performed to clean the intermediate transfer member in order to eliminate this defect. The mode is executed by an instruction from the operator.
JP 2001-134109 A

  However, there is a problem that even if the operator determines the cause of the image defect and executes the mode for eliminating the image defect as in the image forming apparatus, the image defect cannot be solved.

  That is, in the image forming apparatus using the intermediate transfer member, the cause of the image defect is not limited to the adhered matter attached to the intermediate transfer member. When the cause of the image defect is other than the adhered matter adhering to the intermediate transfer member, the image defect is not resolved even if the cleaning mode for cleaning the intermediate transfer member is executed. It is difficult for the operator to appropriately determine the cause of the image defect.

  Here, there is an image defect caused by a change in appropriate conditions for forming a toner image on the image bearing member as another image defect that has a different cause and may frequently occur.

  An object of the present invention is to provide an image forming apparatus having means that allows an operator who is difficult to specify the cause of an image defect to quickly eliminate the image defect.

The above object can be achieved by an image forming apparatus having the following configuration.
(1) an image carrier and toner image forming means for forming a toner image on the image carrier;
Removal means for removing the deposits adhering to the image carrier, detection means for detecting the detected toner image formed on the toner image forming means, and detection result of the detected toner image of the detection means In accordance with the above, in the image forming apparatus having control means for variably controlling the toner image forming condition of the toner image forming means, at least the removal of the deposit by the removing means and the toner to be detected by the detecting means A mode for performing image detection, and execution means for executing the mode;
An image forming apparatus, comprising: an operation unit that causes the execution unit to start executing the mode when operated by an operator of the image forming apparatus.
(2) a step of forming a toner image on the image carrier, a step of removing deposits adhering to the image carrier, a step of detecting a toner image to be detected formed on the image carrier, And a step of variably controlling a toner image forming condition for forming the toner image in accordance with a result of the detection of the toner image to be detected, at least according to an instruction from an operator. An image forming method comprising a step of starting execution of a mode for removing a kimono and detecting the toner image.

  According to the present invention, it is possible for a user who is difficult to identify the cause of an image defect to quickly eliminate the image defect.

[Example 1]
Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a full-color printer as an image forming apparatus. An image forming unit 1Y that forms a yellow image, an image forming unit 1M that forms a magenta image, an image forming unit 1C that forms a cyan image, and an image forming unit 1Bk that forms a black image The four image forming units (image forming units) are provided. These four image forming units 1Y, 1M, 1C, 1Bk are arranged in a line at regular intervals.

  In each of the image forming units (toner image forming means) 1Y, 1M, 1C, and 1Bk, drum type electrophotographic photosensitive members (hereinafter referred to as photosensitive drums) 2a, 2b, 2c, and 2d are installed as image carriers. ing. Around each photosensitive drum 2a, 2b, 2c, 2d, there are primary chargers 3a, 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, transfer rollers 5a, 5b, 5c, 5d as transfer means, Drum cleaner devices 6a, 6b, 6c and 6d are respectively arranged. A laser exposure device 7 is installed below the primary chargers 3a, 3b, 3c, 3d and the developing devices 4a, 4b, 4c, 4d. Further, a power switch 1070 is provided as a power-on means for turning on the image forming apparatus.

  Each developing device 4a, 4b, 4c, and 4d contains yellow toner, cyan toner, magenta toner, and black toner, respectively.

  When the image forming apparatus is turned on by the power switch 1070, the image forming apparatus is started.

  Each of the photosensitive drums 2a, 2b, 2c, and 2d is a negatively charged OPC photosensitive member having a photoconductive layer on an aluminum drum base, and is driven in a direction indicated by an arrow (clockwise in FIG. 1) by a driving device (not shown). Direction) at a predetermined process speed.

  Primary chargers 3a, 3b, 3c, and 3d as primary charging means bring the surface of each photosensitive drum 2a, 2b, 2c, and 2d to a predetermined negative potential by a charging bias applied from a charging bias power source (not shown). Charge uniformly.

  The developing devices 4a, 4b, 4c, and 4d contain toner, and are developed as toner images by attaching toners of respective colors to the electrostatic latent images formed on the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Visualization).

  Transfer rollers 5a, 5b, 5c and 5d as primary transfer means are arranged so as to be in contact with the respective photosensitive drums 2a, 2b, 2c and 2d via the intermediate transfer belt 8 in the respective primary transfer portions 32a to 32d. Yes.

  The drum cleaners 6 a, 6 b, 6 c, 6 d have a cleaning blade or the like for removing, from the photosensitive drum 2, transfer residual toner remaining on the photosensitive drum 2 during the primary transfer.

The intermediate transfer belt 8 is disposed on the upper surface side of each photosensitive drum 2a, 2b, 2c, 2d, and is stretched between the secondary transfer counter roller 10 and the tension roller 11,
The secondary transfer counter roller 10 is disposed in the secondary transfer portion 34 so as to be in contact with the secondary transfer roller 12 via the intermediate transfer belt 8. The intermediate transfer belt 8 is made of a dielectric resin such as polycarbonate, polyethylene terephthalate resin film, polyvinylidene fluoride resin film, or the like.

  The intermediate transfer belt (intermediate transfer member, image carrier) 8 has a primary transfer surface (8b) formed on the surface facing the photosensitive drums 2a, 2b, 2c, and 2d on the secondary transfer roller 12 side. Inclined with the bottom facing down.

  That is, the intermediate transfer belt 8 is movably disposed on the upper surfaces of the photosensitive drums 2a to 2d so that the primary transfer surface (lower flat surface 8b) formed on the surface facing the photosensitive drum 2 is used as the secondary transfer unit. It is inclined and arranged so that the 34 side is downward. Specifically, this inclination angle is set to about 15 °. The intermediate transfer belt 8 is stretched by two rollers, a secondary transfer counter roller 10 and a tension roller 11. The secondary transfer counter roller 10 is disposed on the secondary transfer portion 34 side and applies a driving force to the intermediate transfer belt 8. The tension roller 11 is arranged on the opposite side across the primary transfer portions 32a to 32d and applies tension to the intermediate transfer belt 8. The secondary transfer counter roller (secondary transfer means) 10 is disposed so as to be in contact with the secondary transfer roller 12 via the intermediate transfer belt 8 at the secondary transfer portion 34. Further, a belt cleaning device 13 for removing and collecting the transfer residual toner remaining on the surface of the intermediate transfer belt 8 is installed outside the endless intermediate transfer belt 8 and in the vicinity of the tension roller 11. The belt cleaning device 13 also removes deposits adhering to the intermediate transfer belt 8 in addition to the transfer residual toner. A fixing device 16 having a fixing roller 16a and a pressure roller 16b is installed in a vertical path configuration on the downstream side of the transfer direction of the transfer material P from the secondary transfer unit 34.

  The exposure device 7 includes laser light emitting means for emitting light corresponding to a time-series electric digital pixel signal of given image information, a polygon lens, a reflection mirror, and the like. The exposure device 7 exposes the photosensitive drums 2a, 2b, 2c, and 2d. By exposure, an electrostatic latent image of each color corresponding to image information is formed on the surface of each photosensitive drum 2a, 2b, 2c, 2d charged by each primary charger 3a, 3b, 3c, 3d.

  Next, an image forming operation by the above-described image forming apparatus will be described.

  When an image formation start signal is issued, the photosensitive drums 2a, 2b, 2c, and 2d of the image forming units 1Y, 1M, 1C, and 1Bk that are rotationally driven at a predetermined process speed are respectively connected to the primary chargers 3a, 3b, 3c and 3d are uniformly charged to negative polarity. Then, the exposure device 7 irradiates an image signal, which is color-separated from the outside, from the laser light emitting element, and passes each color on each photosensitive drum 2a, 2b, 2c, 2d via a polygon lens, a reflection mirror, or the like. An electrostatic latent image is formed.

  First, yellow toner is adhered to the electrostatic latent image formed on the photosensitive drum 2a by the developing device 4a to which a developing bias having the same polarity as the charging polarity (negative polarity) of the photosensitive drum 2a is applied. Visualize as an image. This yellow toner image is driven by a transfer roller 5a to which a primary transfer bias (a reverse polarity (positive polarity) to toner) is applied in a primary transfer portion 32a between the photosensitive drum 2a and the transfer roller 5a. Primary transfer is performed on the intermediate transfer belt 8. The primary transfer bias is applied to the transfer roller 5a from the primary transfer bias power source 1060a.

  The intermediate transfer belt 8 onto which the yellow toner image has been transferred is moved to the image forming unit 1M side. Also in the image forming unit 1M, the magenta toner image formed on the photosensitive drum 2b is superimposed on the yellow toner image on the intermediate transfer belt 8 in the same manner as described above, and the primary transfer unit 32b. Transcribed.

  At this time, the transfer residual toner remaining on each photosensitive drum 2 is scraped off and collected by a cleaner blade or the like provided in the drum cleaner devices 6a, 6b, 6c, and 6d.

  Similarly, cyan and black toner images are sequentially superimposed on the yellow and magenta toner images superimposed and transferred on the intermediate transfer belt 8 by the primary transfer portions 32a to 32d. Then, a full-color toner image is formed on the intermediate transfer belt 8.

  Then, the front end of the full color toner image on the intermediate transfer belt 8 is moved to the secondary transfer portion 34 between the secondary transfer counter roller 10 and the secondary transfer roller 12. In accordance with this timing, the transfer material (paper) P selected from the paper feed cassette 17 or the manual feed tray 20 and fed through the transport path 18 is transported to the secondary transfer section 34 by the registration roller 19. A full-color toner image is collectively transferred to the transfer material P conveyed to the secondary transfer unit 34 by the secondary transfer roller 12 to which a secondary transfer bias (polarity opposite to the toner (positive polarity)) is applied. Is done. As the secondary transfer roller 12, a conductive sponge-like rubber roller was used.

  The transfer material P on which the full-color toner image is formed is conveyed to the fixing device 16. The full-color toner image is heated and pressed at the fixing nip portion between the fixing roller 16a and the pressure roller 16b, and is thermally fixed on the surface of the transfer material P. After the fixing, the transfer material P is discharged onto the discharge tray 22 on the upper surface of the main body by the discharge roller 21, and a series of image forming operations is completed. The secondary transfer residual toner or the like remaining on the intermediate transfer belt 8 after the secondary transfer is removed by a cleaning device 13 as a removing unit attached on the intermediate transfer belt 8 to prepare for the next image formation. . The cleaning device 13 in this embodiment employs a blade cleaning method in which a blade-shaped urethane rubber 131 is spring-pressed with a certain contact pressure.

  The above is the image forming operation at the time of single-sided image formation.

  FIG. 2 is a control block diagram in the image forming apparatus. A CPU 171 performs basic control of the image forming apparatus. A ROM 174 in which a control program is written, a work RAM 175 for processing, and an input / output port 173 are connected by an address bus and a data bus. The input / output port 173 is connected to various loads (not shown) such as a motor and a clutch for controlling the image forming apparatus, and an input (not shown) such as a sensor for detecting the position of the paper.

  The CPU 171 sequentially performs input / output control via the input / output port 173 in accordance with the contents of the ROM 174 to execute an image forming operation. An operation unit 172 is connected to the CPU 171 and controls display means and key input means of the operation unit 172. The operator instructs the CPU 171 to change the image forming operation mode and display through the key input means. The CPU 171 displays the state of the image forming apparatus 100 and the operation mode setting by key input. The CPU 171 includes an external I / F processing unit 400 that transmits and receives image data and processing data from an external device such as a PC. Further, an image memory unit 300 that performs image expansion processing and temporary storage processing, and an image forming unit 200 that performs processing for exposing the line image data transferred from the image memory unit 300 to the exposure device 7 are connected. ing.

  Incidentally, the image forming apparatus is capable of gradation image formation. The configuration will be described with reference to the block diagram of the gradation image reproduction process shown in FIG.

  A luminance signal of the image is obtained at the CCD input 1019, and the luminance signal is converted into a digital luminance signal by the A / D conversion circuit 1020. The luminance signal passes through a shading circuit 1021 that corrects sensitivity variations of individual CCD elements, and passes through a LOG converter 1022 in order to convert the corrected luminance signal into a density signal.

  The density signal obtained by the LOG converter 22 is converted by the LUT 1023 in order to correct the γ characteristic of the printer at the initial setting so that the original image density and the output image density match. The LUT 1023 is corrected by an LUT correction table 1024 that is formed by calculation results described later.

  The signal converted by the LUT 1023 is converted into a signal corresponding to the dot width by the pulse width conversion circuit 1025 and sent to the laser driver 1026. With such digital signal processing, a latent image having gradation characteristics due to a change in dot area is formed on each photosensitive drum 2 (2a, 2b, 2c, 2d) by laser scanning, which is called development, transfer, and fixing. A gradation image is obtained through the process.

  The density signal level of this embodiment has 8 bits, that is, 256 gradations. Then, in order to obtain a desired gradation, the density of the toner image is controlled.

  The toner image density control method is as follows.

  As shown in FIG. 4, a toner image condition control pattern (detected toner image) 1027a is formed on the photosensitive drum 1 for five levels of 00H, 40H, 80H, COH, and FFH by a test pattern generator, and further intermediate transfer is performed. Transferred onto the belt 8.

  This image forming apparatus has a built-in test pattern generator on the photosensitive drum 2 (2a, 2b, 2c, 2d) for changing the density signal level by several steps.

  The toner image density control pattern image 1027a formed on the photosensitive drum 2 as described above is sequentially transferred onto the intermediate transfer belt. Thereafter, the output corresponding to each toner optical density of the toner image density control pattern 1027a is detected by the light emitting element 1028 and the light receiving element 1029 as toner image detecting means shown in FIG. FIG. 5 is a graph showing the relationship between the output image density of each color and the output of the light receiving element 1029 in this embodiment.

  Based on the detection results of the light emitting element 1028 and the light receiving element 1029 as detection means, the toner image density control means 1050 controls a look-up table (hereinafter LUT) to control the density of the toner image.

  Details of the control method of the toner image density control means 1050 will be described below.

  A method of creating the LUT correction table 1024 by processing the detection signal read by the light receiving element 1029 and creating the LUT correction table 1024 will be described with reference to the block diagram of FIG. A signal read by the light receiving element 1029 is converted into a digital signal by the A / D converter 1030 and converted into a density signal by the density conversion circuit 1031.

  The density for each density level of the toner image density control pattern image 1027a is set by the LUT 1023 so as to be a curve C shown in FIG. However, the sensitivity, development characteristics, etc. of the photosensitive drum 2 (2a, 2b, 2c, 2d) change due to changes in the toner supply mode, environmental changes, changes over time, etc., and the density with respect to the density level is initial. The curve C changes from the curve C in FIG.

  Therefore, if the detection result of the density obtained from the light receiving element 1029 is higher than the set value as shown by the curve A in FIG. 7, it is increased by the amount increased as shown by the curve A ′ in FIG. Correction calculation is performed so as to lower the setting. On the contrary, when the detection result is lower than the set value as shown by the curve B in FIG. 7, the correction calculation is performed so as to increase from the setting by the lower amount as shown by the curve B ′ in FIG.

  Therefore, the LUT correction table 1024 for correcting the LUT 1023 is created via the correction value calculation circuit 1032 for calculating the correction value as described above from the density calculated by the density conversion circuit 1031 shown in FIG.

  By correcting the LUT 1023 using the LUT correction table 1024 obtained as described above, the changed gradation characteristics can be corrected, and a constant printer gradation characteristic can be obtained at all times. By performing the correction for each color, it is possible to form a toner image having a density suitable for a desired gradation.

  The correction value is stored in the RAM of the control unit (not shown), and is used until the correction is performed again when it is determined that the density of the toner image is abnormal.

  Next, toner image position control will be described.

  As shown in FIG. 9, a toner image position control pattern (detected toner image) 1027b is formed on the intermediate transfer belt 8 facing the light emitting element 1028 and the light receiving element 1029 as detection means. The light emitted from the light emitting element 1028 to the toner image position control pattern 1027b is reflected by the light receiving element 1029.

  Based on the detection result, the toner image position control unit 1051 controls the position where the exposure unit 7 exposes the photosensitive drum 2 to control the position where the toner image is formed.

  FIG. 10 shows details of the toner image formation position control pattern 1027b. In FIG. 10, patterns Ya, Ma, Ca, and Bka are formed on the intermediate transfer belt 8 by the image forming units 1Y, 1M, 1C, and 1Bk, respectively. The patterns Ya, Ma, Ca, and Bka are straight lines in a direction perpendicular to the arrow A direction that is the traveling direction of the intermediate transfer belt 8. The patterns Ya, Ma, Ca, Bka are formed at a predetermined timing. Now, as shown in FIG. 10, the distances la 1, la 2, and la 3 between the patterns Ya, Ma, Ca, and Bka are measured by the light emitting element 1028 and the light receiving element 1029. From the timing at which the patterns Ya, Ma, Ca, and Bka are formed, the ideal distances of la1, la2, and la3 are known.

  The toner image formation position control unit 1051 compares the measured distances la1, la2, and la3 with the ideal distance, and controls the toner image formation position in the horizontal direction and the traveling direction of the intermediate transfer belt 8. At this time, the toner image position control unit 1050 controls the position at which the exposure unit 7 of the image forming units 1Y, 1M, 1C, and 1Bk exposes the photosensitive drum 2.

  In FIG. 10, patterns Yb, Mb, Cb, and Bkb are also formed on the intermediate transfer belt 8 by the image forming units 1Y, 1M, 1C, and 1Bk, respectively. The patterns Yb, Mb, Cb, and Bkb are straight lines formed at a predetermined angle with respect to a direction perpendicular to the arrow A direction that is the traveling direction of the intermediate transfer belt 8. The patterns Yb, Mb, Cb, and Bkb are formed at a predetermined timing. Now, as shown in FIG. 10, the distances lb1, lb2, lb3, lb4 between the two lines in the patterns Yb, Mb, Cb, Bkb are measured by the light emitting element 1028 and the light receiving element 1029. From the timing at which the patterns Yb, Mb, Cb, and Bkb are formed, the ideal distances of lb1, lb2, lb3, and lb4 are known.

  The toner image formation position control unit 1051 compares the measured distances la1, la2, and la3 with the ideal distance, and controls the toner image formation position in the direction perpendicular to the traveling direction of the intermediate transfer belt 8. At this time, the toner image formation position control unit 1050 controls the position at which the exposure unit 7 of the image forming units 1Y, 1M, 1C, and 1Bk exposes the photosensitive drum 2. As described above, the detection unit detects the toner image on the intermediate transfer member. Then, based on the detection result of the detection means, the toner image density control means 1050 and the toner image position control means 1051 as the control means set the toner image forming conditions (toner image density, toner image position) of the toner image forming means. Variable control.

  Next, details of the image memory unit 300 will be described with reference to FIG. The image memory unit 300 writes the image data received from the external I / F processing unit 400 via the memory controller unit 302 to the page memory 301 configured by a memory such as a DRAM, and reads the image to the image forming unit 2. Access image input / output.

  The memory controller unit 302 determines whether the image data from the external device received from the external I / F processing unit 400 is compressed data. If it is determined that the data is compressed data, the decompression process is performed using the compressed data decompression processing unit 303, and then the write process is performed on the page memory 301 via the memory controller unit 302.

  The memory controller unit 302 generates a DRAM refresh signal of the page memory 301 and arbitrates access to the page memory 301 for writing from the image I / F processing unit 400 and reading to the image forming unit 200. Further, in accordance with an instruction from the CPU 171, the write address to the page memory 301, the read address from the page memory 301, and the read direction are controlled.

  The configuration of the external I / F processing unit 400 will be described with reference to FIG.

  The external I / F processing unit 400 receives image data and print command data transmitted from the external device 500 through the interface shown below. As the interface, a USB I / F unit 401, a Centro I / F unit 402, and a network I / F unit 403 are used. Further, the external I / F processing unit 400 transmits the status information of the image forming apparatus determined by the CPU 171 to the external apparatus 500. Here, the external device 500 is a computer, a workstation, or the like.

  Print command data received from the external device 500 via the USB I / F unit 401, the Centro I / F unit 402, or the network I / F unit 403 is processed by the CPU 171 and the print operation is processed by the image forming unit 200 or FIG. A setting and timing for executing a print operation using the I / O 173 of No. 2 are generated.

  Image data received from the external device 500 via the USB I / F unit 401, the Centro I / F unit 402, or the network I / F unit 403 is transmitted to the image memory unit 300 according to the timing based on the print command data. Then, the image forming unit 200 performs processing to form an image.

  Next, when the image forming apparatus is used by a user (operator), a recovery mode used by the user to recover an abnormal image when an abnormal image occurs will be described. The recovery mode is performed when the user depresses the recovery mode starting unit 601 on the operation screen (operation unit) 600 provided in the image forming apparatus shown in FIG. Start.

  When the recovery mode starting unit 601 is pressed, the command data is processed by the CPU (execution unit) 171 in FIG. 2, and the recovery mode is performed using the image forming unit 200 or the like.

  The user can arbitrarily start execution of the recovery mode by operating the starting means 601.

  This embodiment is performed as follows. FIG. 14a shows a flow of a recovery mode sequence in the present embodiment.

  The recovery mode is 1. 1. steps related to removal of deposits on the intermediate transfer belt; 2. Step related to toner image position; The steps relating to the toner image density are performed in this order. When the recovery mode is started, the intermediate transfer belt 8 rotates. Then, after the recovery mode ends, the intermediate transfer belt 8 stops.

  Details of the first step (S1 in FIG. 14a) relating to the removal of deposits on the intermediate transfer belt will be described.

  When the user presses the recovery mode starting means 601, the recovery mode starts, and first, the intermediate transfer belt 8 rotates in the direction of arrow A in FIG. As the intermediate transfer belt 8 rotates, the blade-like urethane rubber (rubber blade) 131 of the cleaning device 13 and the intermediate transfer belt 8 are rubbed and the deposits on the intermediate transfer belt 8 are removed. The intermediate transfer belt 8 is preferably rotated at least once (2.4 seconds). Further, as the time for which the urethane rubber 131 and the intermediate transfer belt 8 are rubbed is longer, the deposits on the intermediate transfer belt 8 can be removed more reliably. In this embodiment, it is rotated 75 times (180 seconds). Here, during the execution of the recovery mode, the intermediate transfer belt 8 continues to rotate without stopping.

  Further, when the urethane rubber 131 and the intermediate transfer belt 8 are rubbed, the presence of toner between the urethane rubber 131 and the intermediate transfer belt 8 allows the urethane rubber 131 to remove deposits on the intermediate transfer belt 8. improves. This is because the toner acts as an abrasive.

  Therefore, in this embodiment, as shown in FIG. 15A, a toner image 1033 as a cleaning toner image is formed on the rotating intermediate transfer belt 8, and the toner is placed between the urethane rubber 131 and the intermediate transfer belt 8. Supply. Here, a method of supplying toner between the urethane rubber 131 and the intermediate transfer belt 8 will be described.

  A belt-like toner image 1033 (perpendicular to the traveling direction of the intermediate transfer belt 8) is formed on the rotating intermediate transfer belt 8 by the image forming unit 1Bk. As shown in FIG. 13, the belt-like toner image 1033 has a length corresponding to the length of the maximum image area in the direction perpendicular to the traveling direction of the intermediate transfer belt 8 and is horizontal to the traveling direction of the intermediate transfer belt 8. It is about 10 cm in length. The size of the belt-like toner image 1033 and the formation timing are recorded in the image memory unit 300 in advance.

  When the toner is supplied between the urethane rubber 131 and the intermediate transfer belt 8, unlike the normal image forming operation, the intermediate transfer belt 8 rotates without performing paper feeding / conveying and secondary transfer. Is done. Along with the rotating intermediate transfer belt 8, the toner image 1033 reaches the urethane rubber 131, and toner is supplied.

  Next, the second step relating to the toner image formation position (S21 and S22 in FIG. 14) will be described.

  As shown in FIG. 15B, a toner image position control pattern 1027b is formed on the intermediate transfer belt 8 (S21). The toner image formation position control pattern 1027b is formed in the image area. Further, the toner image position control pattern is formed on the intermediate transfer belt 8 after the toner image 1033 is formed on the intermediate transfer belt 8 and after the intermediate transfer belt 8 makes one rotation or more. In other words, the toner image formation position control pattern 1027b is formed in the region of the intermediate transfer belt 8 where the depositing material removal operation has been performed by the cleaning device 13.

  The toner image position control pattern 1027b is detected by the light emitting element 1028 and the light receiving element 1029 as detection means (S22).

  Next, the third toner image density step (S31 and S32 in FIG. 14a) will be described. As shown in FIG. 15B, a toner image density control pattern 1027a is formed on the intermediate transfer belt 8 upstream of the toner image forming position control pattern 1027b in the traveling direction of the intermediate transfer belt 13 (FIG. 14a). Middle, S31). The toner image forming condition control pattern image 1027a is formed in the image area. In other words, the toner image density control pattern 1027a is formed in the region of the intermediate transfer belt 8 where the deposit removal operation has been performed by the cleaning device 13.

  The toner image density control pattern 1027a is detected by the light emitting element 1028 and the light receiving element 1029 as toner image detecting means (S32 in FIG. 14a).

  When the control of the density of the toner image is completed, the rotating intermediate transfer belt 8 stops and the recovery mode is completed. Then, after the end of the recovery mode and before the next image is formed, based on the measurement results of the toner image formation position control pattern 1027b and the toner image density control pattern 1027a, the CPU 171 determines the position where the toner image is formed. And the density of the toner image is controlled.

  As described above, by providing a recovery mode that removes deposits attached to the intermediate transfer belt as an image carrier, toner image position control, and toner image density control, a user who has difficulty in identifying the cause of an image defect can be obtained. Thus, it becomes possible to quickly resolve image defects.

  In the method shown in FIG. 14a, the position where the toner image is formed and the density of the toner image are controlled after the end of the recovery mode.

  However, as shown in FIG. 14b, following the step (S22) in which the toner image formation position control pattern 1027b is detected by the light emitting element 1028 and the light receiving element 1029, the position (S23) for forming the toner image is performed. Is also possible.

  Further, as shown in FIG. 14B, the toner image density control (S32) can be performed following the step (S32) in which the toner image density control pattern 1027a is detected by the light emitting element 1028 and the light receiving element 1029. .

  Here, as shown in FIG. 16, the total time for detecting the toner image position control pattern 1027b and the toner image density control pattern 1027a is 63.8 seconds. Less than the required 180 seconds.

  As in this embodiment, the toner image position control pattern 1027b and the toner layer density control pattern 1027a are detected while the deposits on the intermediate transfer belt 8 are being removed. The time during which the image forming apparatus cannot perform image formation is 180 seconds, and the time during which image formation cannot be performed is approximately 55 seconds shorter than the time during which individual control is performed as shown in FIG. As a result, the time required for the recovery mode can be shortened.

(Example 2)
In this embodiment, when a door is assumed to be attached to the intermediate transfer belt as described above using a door switch or the like that can detect that the door has been opened, the description of Embodiment 1 is automatically made. Perform recovery mode.

(Example 3)
FIG. 18 shows an image forming apparatus of this embodiment. Members having the same configuration and effects as those of the image forming apparatus shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 18, reference numerals 1061 a to 106 d denote transfer voltage detection units that detect voltages generated when the transfer power supplies 1060 a to 1060 d apply a bias having a predetermined current value to the transfer roller 5. The transfer voltages 1062a to 1062d control the bias voltage applied to the transfer roller 5 when transferring the toner image from the image carrier 2 to the intermediate transfer belt 8 based on the detection results of the transfer voltage detection means 1061a to 1061d. It is a control means.

  In this embodiment, at least before the toner image density control pattern 1027a is detected in the recovery mode described in the first embodiment, the bias applied to the transfer roller 5 by the transfer voltage control means 1062a, 1062b, 1062c, and 1062d. To control the voltage. FIG. 19 shows a recovery mode sequence according to this embodiment.

Example 4
FIG. 20A shows the operation unit of this embodiment. When the user depresses the deposit removal start means 701 of the intermediate transfer belt 8 on the operation screen 700, the deposit adhered to the intermediate transfer belt 8 described in the first embodiment is removed. Here, the user may press the setting mode button 702 on the operation screen 700 of FIG. 20A to shift to the setting screen and select whether or not to perform toner image formation position control and toner image formation condition control. it can.

  FIG. 21a shows a flow for selecting whether to perform toner image position control and toner image density control.

  This will be described with reference to FIG. 21a.

  FIG. 20B is a setting screen for selecting whether or not image adjustment is performed. The user selects whether or not to perform toner image formation position control and toner image formation condition control simultaneously with the removal of the adhering matter adhered to the intermediate transfer belt 8 by the control selection means 703 (S1 in FIG. 21a).

  When the user selects not to perform the toner image position control and the toner image density control at the same time, and presses the deposit removal start unit 701 to remove the deposit, the operation screen as shown in FIG. Transition. Then, the user is informed that only the deposits on the intermediate transfer belt 8 are to be removed, and the deposits on the intermediate transfer belt 8 are removed (S31 and S32 in FIG. 21a). If the user selects to perform toner image position control and toner image density control at the same time, the toner image position control pattern 1027b and the toner image density are followed by the deposit removal operation (S21 and S22 in FIG. 21a). A control pattern 1027a is formed. Then, the toner image position control pattern 1027b and the toner image density control pattern 1027a are detected (S23 in FIG. 21a). Then, the control of the toner image forming position and the toner image density are performed after the recovery mode is completed by the completion of the removal of the adhering material and before the next image formation.

  As shown in FIG. 21b, the CPU 171 controls the toner image formation position and the toner image density after S23 and before the adhering matter removal end (S24 in FIG. 21b). May be.

(Example 5)
FIG. 22 shows another form of the deposit removal mode execution start means. The user is a view showing means for removing the deposit on the intermediate transfer belt 8 on the operation screen 800 on the computer or workstation. When the user presses the deposit removal start means 801 on the operation unit 800, the operations of deposit removal, toner image formation position control, and toner image formation condition control of the intermediate transfer belt 8 described above are started. Here too, the control selection means 802 as described in the fifth embodiment (FIG. 20B) allows the user to select whether or not to perform toner image position control and toner image density control at the same time as the removal of deposits. It becomes.

1 is a schematic configuration diagram of an image forming apparatus according to a first exemplary embodiment. FIG. 3 is a control block diagram of the image forming apparatus according to the first exemplary embodiment. 3 is a control block diagram of image gradation of the image forming apparatus of Embodiment 1. FIG. FIG. 3 is a diagram illustrating a toner image forming condition control pattern of the image forming apparatus according to the first exemplary embodiment. It is a graph which shows the output density of each color, and the output relationship of a light receiving element. It is a block diagram which creates a LUT correction table. FIG. 6 is a diagram illustrating a relationship of density to a density level of a toner image forming condition control pattern. FIG. 3 is a diagram illustrating a toner image formation position control pattern of the image forming apparatus according to the first exemplary embodiment. The figure which shows the relationship of the output level with respect to an input level. FIG. 3 is a diagram illustrating details of a toner image formation position control pattern of the image forming apparatus according to the first exemplary embodiment. 2 is a diagram illustrating an image memory unit of the image forming apparatus according to the first exemplary embodiment. FIG. 2 is a diagram illustrating an external I / F processing unit of the image forming apparatus according to the first exemplary embodiment. FIG. 6 is a diagram illustrating a display example by an operation unit of the image forming apparatus of Embodiment 1. FIG. a is a figure which shows the flow of a sequence of recovery mode. b is a diagram showing a flow of another sequence in the recovery mode. FIG. 6 is a diagram illustrating a toner image formed on an intermediate transfer belt in a recovery mode. It is a figure which shows the sequence of recovery mode. It is a figure which shows another example of the sequence of recovery mode. FIG. 6 is a schematic configuration diagram of an image forming apparatus according to a third embodiment. It is a figure which shows the sequence of the recovery mode of Example 2. FIG. a, b, and c are diagrams illustrating display examples of the operation unit according to the fourth embodiment. FIG. 9A is a diagram illustrating a flow when the selection unit according to the fourth embodiment is used. b is a diagram showing another flow when the selection means of the fourth embodiment is used. FIG. 10 illustrates an operation unit according to a fifth embodiment.

Explanation of symbols

1Y, 1M, 1C, 1Bk Image forming portions 2a, 2b, 2c, 2d Photosensitive drum (image carrier)
3a, 3b, 3c, 3d Primary charger (charging means)
4a, 4b, 4c, 4d Developing device (developing means)
5a, 5b, 5c, 5d Transfer roller (primary transfer means)
6a, 6b, 6c, 6d Drum cleaner device (cleaner means)
7 Exposure equipment (exposure means)
7a Lower surface 7b Lower end 8 Intermediate transfer belt 8a Top surface 8b Lower plane (primary transfer surface)
10 Secondary transfer counter roller 11 Tension roller 12 Secondary transfer roller (secondary transfer means)
16 Fixing device (fixing means)
16a Fixing roller 16b Heating roller 17 Paper feed cassette 18 Transport path 21 Paper discharge roller (discharge means)
22 Paper discharge tray 30 Toner container 31 Nipping part (heating and pressing position)
32a, 32b, 32c, 32d Primary transfer unit 34 Secondary transfer unit 600, 700, 800 Operation unit 601, 701, 801 Recovery mode execution start means 702 Setting mode buttons 703, 802 selection means

Claims (6)

An image carrier;
Toner image forming means for forming a toner image on the image carrier;
Removing means for removing deposits adhering to the image carrier;
Detecting means for detecting a toner image for detection formed on the toner image forming means;
An image forming apparatus having a control unit that variably controls a toner image forming condition of the toner image forming unit in accordance with a detection result of the toner image to be detected by the detecting unit.
A mode for performing at least the removal of the deposit by the removal unit and the detection of the toner image for detection by the detection unit; and an execution unit for executing the mode;
An image forming apparatus, comprising: an operation unit that causes the execution unit to start executing the mode when operated by an operator of the image forming apparatus.   The image forming apparatus according to claim 1, wherein the toner image forming condition is a position and density of the toner image formed by the toner image forming unit on the image carrier.   3. The image according to claim 2, wherein in the mode, the detection unit detects the toner image formed in a region of the image carrier on which the removal unit has performed the removal operation of the attached matter. Forming equipment. Forming a toner image on the image carrier;
Removing deposits adhering to the image carrier;
Detecting a toner image for detection formed on the image carrier;
A step of variably controlling a toner image forming condition for forming the toner image according to a result of the detection of the toner image for detection.
An image forming method comprising: starting execution of a mode for performing at least the removal of the attached matter and the detection of the toner image in accordance with an instruction from an operator.   5. The image forming method according to claim 4, wherein the toner image forming conditions are a position and a density of the toner image on the image carrier. 6. The image forming method according to claim 5, wherein, in the mode, the detection unit detects the toner image formed on the area of the image carrier on which the deposit removal operation has been performed.

Images