Image forming apparatus

Abstract

To improve productivity compared to a case where image quality adjustment for image forming means is performed after completion of warming.SOLUTION: An image forming apparatus (U) comprises: image forming means (LHy-LHk) that form images; warming means (6) that warms the image forming means (LHy-LHk); detection means (SN1) that detects the images held on image holding means (B); adjustment means (C6) that executes first adjustment of adjusting the image quality of an image based on a result of detection performed by the detection means (SN1), and second adjustment of adjusting the image quality not based on a result of detection performed by the detection means (SN1); and warming control means (C5) that controls the warming means (6) to increase the temperature of the image forming means (LHy-LHk) to a predetermined temperature, the warming control means (C5) increasing the temperature in a period overlapping a period during which the second adjustment is executed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art In an image forming apparatus, the techniques described in Patent Documents 1 and 2 below are conventionally known in relation to an electrophotographic image forming apparatus that forms an image by irradiating light onto an image holding means.

[0003] Patent Document 1 (JP 2008-93855 A) describes a technology for correcting the exposure position shift caused by thermal expansion of the substrate due to heat generated when the light-emitting elements emit light, by arranging a heating means (28) for heating the substrate and an auxiliary heating means (72) for auxiliary heating the substrate along a substrate (22) on which light-emitting elements are arranged along the main scanning direction, thereby shortening the time required for the substrate (22) to reach a predetermined temperature.

[0004] Patent Document 2 (JP Patent Publication No. 2008-216861) describes a technology in which light-emitting elements (63) are arranged on a first surface of a substrate (62), and the substrate (62) is heated from the first surface side by a heating means (65), thereby adjusting the amount of thermal expansion of the substrate (62) to correspond to the amount of positional misalignment of the LEDs, thereby reducing image misalignment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-93855 A (Claim 1, "0032"-"0067") [Patent Document 2] JP 2008-216861 A ("0025", "0035"-"0047") Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has a technical object to improve productivity compared to when image quality adjustment of the image forming means is performed after heating is completed. [Means for solving the problem]

[0007] In order to solve the above technical problem, the image forming apparatus of the invention described in claim 1 comprises: an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; a detection means for detecting the image held by the image holding means; an adjustment means for performing a first adjustment for adjusting the image quality of an image based on the detection result of the detection means, and a second adjustment for adjusting the image quality not based on the detection result of the detection means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; The present invention is characterized by the following features.

[0008] In order to solve the above technical problem, the image forming apparatus of the invention described in claim 2 comprises: an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjustment means for performing a first adjustment for adjusting the image quality when the temperature of the image forming means reaches a predetermined temperature, and a second adjustment for adjusting the image quality regardless of the temperature of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; The present invention is characterized by the following features.

[0009] In order to solve the above technical problem, the image forming apparatus of the invention described in claim 3 comprises: an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjustment means for performing a first adjustment that involves adjusting control of the image forming means and a second adjustment that does not involve adjusting control of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; The present invention is characterized by the following features.

[0010] The invention described in claim 4 is the image forming apparatus described in any one of claims 1 to 3, the heating means has a plurality of light-emitting elements that output light to form an image, and the light-emitting elements are arranged in a line along the scanning direction of the image, and are heated by heat generated by the exposure means when current is passed through a drive circuit that drives the exposure means, or by heat generated by a heater that heats the exposure means; It is characterized by:

[0011] The invention described in claim 5 is the image forming apparatus according to any one of claims 1 to 3, the adjusting means for performing the first adjustment for adjusting the density of an image formed by the image forming means; The present invention is characterized by the following features.

[0012] The invention described in claim 6 is the image forming apparatus described in any one of claims 1 to 3, the adjusting means for performing the first adjustment to adjust the position of the image formed by the image forming means; The present invention is characterized by the following features.

[0013] The invention described in claim 7 is the image forming apparatus described in any one of claims 1 to 3, a developing means for developing the image formed on the image holding means by the image forming means with a developer; the second adjustment for discharging the developer from the developing means to the image holding means; The present invention is characterized by the following features.

[0014] The invention described in claim 8 is the image forming apparatus according to any one of claims 1 to 3, the adjusting means for, when the first adjustment and the second adjustment are executed, executing the second adjustment and then the first adjustment in that order, and for heating the image forming means during the execution of the second adjustment; The present invention is characterized by the following features.

[0015] The invention described in claim 9 is the image forming apparatus described in claim 8, the adjusting means for starting the first adjustment after the second adjustment is finished and heating is completed; The present invention is characterized by the following features.

[0016] The invention described in claim 10 is the image forming apparatus according to any one of claims 1 to 3, a transfer means for transferring an image from the image holding means to a medium, the transfer means being movable between a contact position where it contacts the image holding means and a separation position where it is separated from the image holding means; an adjusting unit that, when at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the separation position and at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the contact position, prioritizes performing the adjustment when the transfer unit is moved to the separation position; The present invention is characterized by the following features.

[0017] The invention described in claim 11 is the image forming apparatus described in claim 10, when the first adjustment is performed with the transfer means moved to the separation position and the second adjustment is performed with the transfer means moved to the contact position, and when a time obtained by adding a period of the second adjustment to a moving time of the transfer means moving between the contact position and the separation position is shorter than a length of the heating period, the adjustment means reverses the order of performing the first adjustment and the second adjustment and performs the second adjustment first; The present invention is characterized by the following features. [Effects of the Invention]

[0018] According to the inventions set forth in claims 1, 2 and 3, productivity can be improved compared to when image quality adjustment of the image forming means is performed after heating is completed. According to the invention of claim 4, heating can be achieved by energizing a drive circuit of an exposure means in which a plurality of light emitting elements are arranged in a line along the operation direction, or by heat generation from a heating zone. According to the invention as set forth in claim 5, the density of the image can be adjusted by the first adjustment. According to the invention as set forth in claim 6, the position of the image can be adjusted by the first adjustment. According to the seventh aspect of the present invention, the deteriorated developer can be discharged in the second adjustment, thereby adjusting the image quality.

[0019] According to the eighth aspect of the invention, degradation of image quality can be suppressed compared to when the second adjustment is performed after the first adjustment. According to the ninth aspect of the present invention, it is possible to suppress the adverse effect of incomplete heating of the image forming means on the first adjustment, compared to when the first adjustment is performed before the heating is completed. According to the invention described in claim 10, it is possible to move quickly to image forming operations after the adjustment is completed, compared to when the adjustment is first performed while the transfer means is moved to the contact position, thereby improving productivity. According to the invention of claim 11, the time required for image forming operation can be shortened and productivity can be improved compared to when the execution order of the first adjustment and the second adjustment is not switched. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is an explanatory diagram of the entire image forming apparatus according to the first embodiment. [Figure 2] FIG. 2 is an explanatory diagram of the main part of the image recording unit of the first embodiment. [Figure 3] FIG. 3 is an explanatory diagram of the exposure apparatus of the first embodiment. [Figure 4] FIG. 4 is a functional block diagram of the control unit according to the first embodiment. [Figure 5] FIG. 5 is an explanatory diagram for comparing the first embodiment with the conventional configuration in the pattern of the adjustment operation, and is an explanatory diagram for patterns No. 1 to No. 8. [Figure 6] FIG. 6 is a continuation of FIG. 5 and is an explanatory diagram of patterns No. 9-1 to No. 13-2. [Figure 7] FIG. 7 is a continuation of FIG. 6 and is an explanatory diagram of patterns No. 14 to No. 15-2. [Figure 8] FIG. 8 is a flowchart of the image quality adjustment process according to the first embodiment. [Figure 9] 9A is a flowchart continuing from ST14 in FIG. 8, FIG. 9B is a flowchart continuing from ST13 in FIG. 8, and FIG. 9C is a flowchart continuing from ST12 in FIG. [Figure 10] FIG. 10 is a flowchart continuing from ST9 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, examples of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. To facilitate understanding of the following explanation, in the drawings, the front-to-back direction is defined as the X-axis direction, the left-to-right direction as the Y-axis direction, and the up-down direction as the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, and -Z are defined as the front, rear, right, left, upper, and lower, or the front side, rear side, right side, left side, upper side, and lower side, respectively. In addition, in the figures, a circle with a "·" inside it means an arrow pointing from the back to the front of the page, and a circle with an "x" inside it means an arrow pointing from the front to the back of the page. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding. [Example]

[0022] FIG. 1 is an explanatory diagram of the entire image forming apparatus according to the first embodiment. 1, a copier U as an example of an image forming apparatus according to a first embodiment of the present invention has a printer unit U1 as an example of an image recording means and an example of an image recording device. A scanner unit U2 as an example of a reading means and an example of an image reading device is supported above the printer unit U1. An auto feeder U3 as an example of a document conveying device is supported above the scanner unit U2.

[0023] Above the auto feeder U3, there is disposed a document tray TG1 as an example of a medium storage means. The document tray TG1 can store a plurality of documents Gi to be copied in a stacked manner. Below the document tray TG1, there is disposed a document discharge tray as an example of a document discharge section. Between the document tray TG1 and the document discharge tray TG2, document transport rollers U3b are arranged along the document transport path U3a.

[0024] A platen glass PG, which is an example of a transparent document table, is disposed on the upper surface of the scanner unit U2. In the scanner unit U2 of the first embodiment, a reading unit U2a, which is an example of a reading unit, is disposed below the platen glass PG. The reading unit U2a of the first embodiment is supported along the lower surface of the platen glass PG so as to be movable in the left-right direction, which is an example of a sub-scanning direction. The reading unit U2a is electrically connected to the image processing unit GS.

[0025] FIG. 2 is an explanatory diagram of the main part of the image recording unit of the first embodiment. The image processing unit GS is electrically connected to a writing circuit DL of the printer unit U1, which is electrically connected to exposure devices LHy, LHm, LHc, and LHk as an example of an image forming means. The exposure devices LHy to LHk of the first embodiment are configured, for example, by an LED head in which a plurality of LEDs (Light Emitting Diodes), which are an example of light emitting elements, are arranged on a substrate along the main scanning direction. The exposure devices LHy to LHk are configured to be able to output writing light corresponding to each of the colors Y, M, C, and K in accordance with a signal input from a writing circuit DL. The write circuit DL and the power supply circuit E have their write timing and power supply timing controlled in response to control signals from a control unit C, which is an example of a control means. In Fig. 1, photoconductors PRy, PRm, PRc, and PRk, which are an example of image holding means, are arranged above exposure devices LHy to LHk. In Fig. 1 and Fig. 2, writing areas Q1y, Q1m, Q1c, and Q1k are formed by areas on each of photoconductors PRy to PRk where writing light is irradiated.

[0026] Charging rollers CRy, CRm, CRc, and CRk, which are an example of charging means, are disposed upstream of the writing areas Q1y to Q1k in the rotation direction of the photoconductors PRy to PRk. The charging rollers CRy to CRk in the first embodiment are supported in contact with the photoconductors PRy to PRk so as to be rotatable by the photoconductors PRy to PRk. Developing devices Gy, Gm, Gc, and Gk, which are an example of developing means, are arranged downstream of the writing areas Q1y to Q1k in the rotation direction of the photoconductors PRy to PRk. The areas where each of the photoconductors PRy to PRk and each of the developing devices Gy to Gk face each other form developing areas Q2y, Q2m, Q2c, and Q2k.

[0027] Primary transfer rollers T1y, T1m, T1c, and T1k, which serve as an example of primary transfer means, are disposed downstream of the developing devices Gy-Gk in the direction of rotation of the photosensitive members PRy-PRk. Primary transfer regions Q3y, Q3m, Q3c, and Q3k are formed by regions where the photosensitive members PRy-PRk and the primary transfer rollers T1y-T1k face each other. Photoconductor cleaners CLy, CLm, CLc, and CLk, which are an example of cleaning means, are arranged downstream of the primary transfer rollers T1y to T1k with respect to the rotation direction of the photoconductors PRy to PRk. Dischargers Jy, Jm, Jc, and Jk, which are an example of a discharge means and an example of a discharge device, are arranged downstream of the photoconductor cleaners CLy to CLk in the rotation direction of the photoconductors PRy to PRk.

[0028] The Y photoconductor PRy, charging roller CRy, exposure device LHy, developing device Gy, primary transfer roller T1y, photoconductor cleaner CLy, and static eliminator Jy constitute a Y image forming unit Uy that forms a Y toner image and is an example of a Y visible image forming means in Example 1. Similarly, the M, C, and K image forming units Um, Uc, and Uk are constituted by the photoconductors PRm, PRc, and PRk, charging rollers CRm, CRc, and CRk, exposure devices LHm, LHc, and LHk, developing devices Gm, Gc, and Gk, primary transfer rollers T1m, T1c, and T1k, photoconductor cleaners CLm, CLc, and CLk, and static eliminators Jm, Jc, and Jk.

[0029] A belt module BM, which is an example of an intermediate transfer device, is disposed above the photoreceptors PRy to PRk. The belt module BM is an example of an image holding means, and has an intermediate transfer belt B, which is an example of an intermediate transfer means. The intermediate transfer belt B is made of an endless belt-shaped member. The intermediate transfer belt B in the first embodiment is rotatably supported by a tension roller Rt as an example of a tensioning means, a walking roller Rw as an example of a deviation correcting means, an idler roller Rf as an example of a driven means, a backup roller T2a as an example of an opposing means in the secondary transfer region, primary transfer rollers T1y to T1k, and a drive roller Rd as an example of a drive member. In the first embodiment, when drive is transmitted to the drive roller Rd, the intermediate transfer belt B rotates. Further, an image detection sensor SN1 as an example of a detection means for detecting an image on the intermediate transfer belt B is disposed downstream of the primary transfer rollers T1y to T1k and between the backup roller T2a, facing the surface of the intermediate transfer belt B.

[0030] A secondary transfer roller T2b, which is an example of a transfer means and an example of a secondary transfer means, is disposed at a position opposite the backup roller T2a across the intermediate transfer belt B. The backup roller T2a and the secondary transfer roller T2b constitute a secondary transfer unit T2 of the first embodiment, which is an example of a transfer device. The area where the secondary transfer roller T2b and the intermediate transfer belt B contact each other constitutes a secondary transfer area Q4. The secondary transfer roller T2b in the first embodiment is configured to be movable between a contact position where it contacts the intermediate transfer belt B and a separation position where it is separated from the intermediate transfer belt B. A belt cleaner CLb, which is an example of a cleaning device for the intermediate transfer member, is disposed downstream of the secondary transfer region Q4 in the rotation direction of the intermediate transfer belt B. The primary transfer rollers T1y to T1k, the intermediate transfer belt B, the secondary transfer device T2, etc. constitute the transfer device T1+T2+B of Example 1. The image forming units Uy to Uk and the transfer device T1+T2+B constitute the image recording units Uy to Uk+T1+T2+B of Example 1.

[0031] 1, four pairs of left and right guide rails GR, which serve as an example of a guide means, are provided below the imaging units Uy to Uk. Each guide rail GR supports paper feed trays TR1, TR2, TR3, and TR4, which serve as an example of a medium storage means, so that they can be moved in and out in the front-rear direction. Each of the paper feed trays TR1 to TR4 stores recording paper S, which serves as an example of a medium. A pickup roller Rp, which is an example of a take-out device, is arranged above and to the left of the paper feed trays TR1 to TR4. A separation roller Rs, which is an example of a separation device, is arranged downstream of the pickup roller Rp in the transport direction of the recording paper S. A paper feed path SH1, which is an example of a medium transport path, is formed downstream of the separation roller Rs in the transport direction of the recording paper S and extends upward. A plurality of transport rollers Ra, which are an example of a transport device, are arranged on the paper feed path SH1.

[0032] A manual feed tray TR0, which serves as an example of a medium storage means, is located in the lower left of the copier U. A pickup roller Rp0 is located in the upper right of the manual feed tray TR0, and a manual feed path SH0 extends from the manual feed tray TR0. The manual feed path SH0 merges with the feed path SH1. In the sheet feed path SH1, a registration roller Rr as an example of a conveyance timing adjustment unit is disposed upstream of the secondary transfer area Q4. A conveyance path SH2 extends from the registration roller Rr toward the secondary transfer area Q4.

[0033] A fixing device F, which is an example of a fixing means, is disposed downstream of the secondary transfer area Q4 in the conveyance direction of the recording paper S. The fixing device F has a heating roller Fh, which is an example of a fixing member for heating, and a pressure roller Fp, which is an example of a fixing member for applying pressure. The contact area between the heating roller Fh and the pressure roller Fp forms a fixing area Q5. A lower paper output tray TRh, which is an example of a medium output unit, is formed on the upper surface of the printer unit U1. In the first embodiment, a finisher U4, which is an example of a post-processing device, is installed in the lower paper output tray TRh. A paper output path SH3, which is an example of a transport path, extends toward the lower paper output tray TRh above the fixing device F. A paper output roller Rh, which is an example of a medium transport means, is disposed at the downstream end of the paper output path SH3.

[0034] An upper discharge tray TRh2, which is an example of a medium discharge section, is disposed above the lower discharge tray TRh. An upper conveyance path SH4 is formed above the fixing device F, branching off from the discharge path SH3 and extending toward the upper discharge tray TRh2. A reversible roller Rb, which serves as an example of a medium transport means, is disposed on the upper transport path SH4. A reversing path SH6, which serves as an example of a medium transport path, branches off from the upper transport path SH4 to the lower left above the branch point of the discharge path SH3 and the upper transport path SH4.

[0035] A gate GT1, which is an example of a switching means, is disposed across the branching portion between the discharge path SH3 and the upper conveying path SH4, and the branching portion between the upper conveying path SH4 and the reverse path SH6. The gate GT1 guides the recording paper S from the fixing device F toward the lower discharge tray TRh, and is supported switchably between a first guide position (second position) where the gate GT1 guides the recording paper S from the fixing device F toward the reverse path SH6 from the upper conveying path SH4, and a second guide position (first position) where the gate GT1 guides the recording paper S from the fixing device F to the upper conveying path SH4. A plurality of conveying rollers Ra, which are an example of a medium conveying means, are arranged on the reverse path SH6. The downstream end of the reverse path SH6 joins with the paper feed path SH1 on the upstream side of the registration rollers Rr.

[0036] (Explanation of image formation operation) In the copier U of the first embodiment having the above configuration, when an operator manually places an original Gi on the platen glass PG to make a copy, the reading unit U2a moves left and right from the initial position, and the original Gi on the platen glass PG is exposed to light and scanned. When the auto feeder U3 is used to automatically transport and copy the original Gi, multiple originals Gi stored in the original tray TG1 are transported sequentially to and pass through the original reading position on the platen glass PG, and then discharged onto the original discharge tray TG2. Each original Gi passing sequentially through the reading position on the platen glass PG is exposed to light and scanned by the reading unit U2a. Reflected light from the original Gi is received by the reading unit U2a. The reading unit U2a converts the received reflected light from the original Gi into an electrical signal. When double-sided reading of the original Gi is performed, the original Gi is also read by a reading sensor.

[0037] The image processing unit GS receives the electrical signals output from the reading unit U2a. The image processing unit GS converts the electrical signals of the R, G, and B color image read by the reading unit U2a into image information of yellow (Y), magenta (M), cyan (C), and black (K) for forming a latent image. The image processing unit GS outputs the converted image information to the writing circuit DL of the printer unit U1. Note that if the image is a single-color image, or a so-called monochrome image, the image processing unit GS outputs image information of only black (K) to the writing circuit DL. The writing circuit DL outputs a control signal corresponding to the input image information to the exposure devices LHy to LHk, which then output writing light according to the control signal.

[0038] When image formation begins, each photoconductor PRy-PRk is driven to rotate. A charging voltage is applied to the charging rollers CRy-CRk from a power supply circuit E. Therefore, the surfaces of the photoconductors PRy-PRk are charged by the charging rollers CRy-CRk. An electrostatic latent image is formed on the surface of the charged photoconductors PRy-PRk by exposure devices LHy-LHk in writing areas Q1y-Q1k. The electrostatic latent image on the photoconductors PRy-PRk is developed into a toner image, an example of a visible image, by developing devices Gy-Gk in development areas Q2y-Q2k.

[0039] The developed toner images are transported to primary transfer regions Q3y-Q3k that come into contact with intermediate transfer belt B, which is an example of an intermediate transfer body. In primary transfer regions Q3y-Q3k, a primary transfer voltage of a polarity opposite to the charge polarity of the toner is applied from a power supply circuit E to primary transfer rollers T1y-T1k. Therefore, the toner images on each photoconductor PRy-PRk are transferred to intermediate transfer belt B by primary transfer rollers T1y-T1k. In the case of a multi-color toner image, the toner image transferred downstream is superimposed on the toner image transferred to intermediate transfer belt B in the upstream primary transfer region. After the primary transfer, residues and deposits on the photoconductors PRy to PRk are cleaned by photoconductor cleaners CLy to CLk. After cleaning, the surfaces of the photoconductors PRy to PRk are neutralized by static eliminators Jy to Jk. After neutralization, the surfaces of the photoconductors PRy to PRk are recharged by charging rollers CRy to CRk. The single-color or multi-color toner images transferred onto the intermediate transfer belt B by the primary transfer rollers T1y to T1k in the primary transfer areas Q3y to Q3k are transported to the secondary transfer area Q4.

[0040] The recording paper S on which an image is recorded is picked up by the pickup roller Rp of the paper feed tray TR1 to TR4 being used. If multiple sheets of recording paper S are picked up by the pickup roller Rp and are stacked, they are separated one by one by the separation roller Rs. The recording paper S separated by the separation roller Rs is transported along paper feed path SH1 by the transport roller Ra. The recording paper S transported along paper feed path SH1 is sent to the registration roller Rr. Recording paper S loaded on the manual feed tray TR0 is also sent to paper feed path SH1 by the pickup roller Rp0 via manual feed path SH0. The registration roller Rr transports the recording paper S to the secondary transfer area Q4 at the same time that the toner image formed on the intermediate transfer belt B is transported to the secondary transfer area Q4. A secondary transfer voltage of a polarity opposite to the charge polarity of the toner is applied to the secondary transfer roller T2b by the power supply circuit E. Therefore, the toner image on the intermediate transfer belt B is transferred from the intermediate transfer belt B to the recording paper S.

[0041] After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLb to remove any foreign matter adhering to the surface thereof. The recording paper S onto which the toner image has been secondarily transferred is heated and fixed when passing through a fixing area Q5. If post-processing is to be performed on the recording paper S with the image fixed thereon, the recording paper S is transported to the finisher U4 installed in the lower paper output tray TRh. If post-processing is not to be performed on the recording paper S, the recording paper S is transported to the upper paper output tray TRh2. When the recording paper S is transported to the lower paper output tray TRh, the gate GT1 moves to the first guide position. Therefore, the recording paper S sent out from the fixing device F is transported along the paper output path SH3. The recording paper S transported along the paper output path SH3 is transported by the paper output roller Rh toward the finisher U4 and the lower paper output tray TRh. The finisher U4 performs binding processing, which is an example of post-processing, on the recording sheets S, and then discharges the recording sheets S onto a lower discharge tray TRh.

[0042] When the recording paper S is discharged onto the upper discharge tray TRh2, the gate GT1 moves to the second guide position, and the recording paper S is discharged onto the upper discharge tray TRh2. When double-sided printing is performed on the recording paper S, the gate GT1 moves to the second guide position. Then, when the trailing edge of the recording paper S passes through the gate GT1, the gate GT1 moves to the first guide position and the reversing roller Rb rotates in the reverse direction. Therefore, the recording paper S is guided by the gate GT1 and sent to the reversing path SH6. The recording paper S transported along the reversing path SH6 is sent to the registration roller Rr in an inverted state.

[0043] (Explanation of exposure equipment) FIG. 3 is an explanatory diagram of the exposure apparatus of the first embodiment. In FIG. 3, the exposure devices LHy to LHk of Example 1 have a frame 1 as an example of a frame. The frame 1 extends along the main scanning direction. A substrate 2 extending along the main scanning direction is supported on the frame 1. An LED array 3 is arranged on the substrate 2, with a plurality of LEDs as an example of light-emitting elements arranged along the main scanning direction of the substrate 2. A refractive index distribution lens array 4 as an example of an optical element is supported on the frame 1 on the side of the LED array 3 facing the photoconductors PRy to PRk. An exposure heater 6 as an example of a heating means is supported on the frame 1 on the side opposite the photoconductors PRy to PRk. In Example 1, a thermistor 7 as an example of a temperature measuring means for measuring the temperature of the exposure devices LHy to LHk is also arranged on the frame 1. The exposure heater 6 can be configured to extend along the bottom surface of the substrate 2, or multiple exposure heaters 6 can be arranged at intervals along the main scanning direction. Furthermore, in the exposure apparatuses LHy to LHk of Example 1, the LED array 3 and the exposure heater 6 are arranged on opposite sides of the substrate 2, but they can also be arranged on the same side. In the first embodiment, the exposure heater 6 is provided to heat the frame 1, but this is not limiting. It is also possible to use heat generated by driving and energizing the drive circuit of the LED array 3 on the substrate 2 for heating, i.e., to use the drive circuit as a heating means.

[0044] (Explanation of the control unit of the first embodiment) FIG. 4 is a functional block diagram of the control unit according to the first embodiment. In FIG. 4, the control unit (controller) C of the copier U has an input / output interface I / O for inputting and outputting signals to and from the outside. The control unit C also has a ROM (read-only memory) in which programs and information for performing necessary processing are stored. The control unit C also has a RAM (random access memory) for temporarily storing necessary data. The control unit C also has a CPU (central processing unit) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit C in Example 1 is configured by a small information processing device, a so-called microcomputer. Therefore, the control unit C can realize various functions by executing programs stored in the ROM or the like. The control unit C of the first embodiment receives a signal from the signal output element and outputs a signal to the controlled element to control it.

[0045] (Description of signal output elements) The control unit C receives signals from signal output elements such as the user interface UI, the image detection sensor SN1, the thermistor 7, and other sensors (not shown). The user interface UI inputs the information entered by the user or worker to the control unit C. The image detection sensor SN1 detects the position and density of the image formed on the intermediate transfer belt B, and outputs the detection result to the control unit C. The thermistor 7 measures the temperature of the LED array 3 and outputs the measurement result to the control unit C.

[0046] (Description of controlled element) The control unit C outputs signals to a power supply circuit E, an exposure heater control circuit D1, a spacing control circuit D2, and other controlled elements (not shown). The power supply circuit E controls the charging bias of the charging rollers CRy to CRk, the developing bias of the developing devices Gy to Gk, the primary transfer bias of the primary transfer rollers T1y to T1k, the secondary transfer bias of the secondary transfer roller T2b, and the power supply to the heater of the fixing device F. The exposure heater control circuit D1 controls the activation and deactivation of the exposure heater 6. The separation control circuit D2 controls the separation motor M1 to bring the secondary transfer roller T2b into contact with or separate from the intermediate transfer belt B.

[0047] (Function of control unit C) The control unit C of the first embodiment has the following functional means (functional modules, program modules). The job control unit C1 controls a job, which is an image forming operation. When a job is started, the job control unit C1 controls the photoconductors PRy to PRk, the power supply circuit E, etc., to form an image on the recording paper S. The image quality detection means C2 detects the image quality, such as the position and density of the image of each color, based on the detection result of the image detection sensor SN1. In the first embodiment, when image quality adjustment is performed, a predetermined image for image quality adjustment is formed, transferred onto the intermediate transfer belt B, and read by the image detection sensor SN1.

[0048] The temperature detection means C3 measures the temperature of the LED array 3 based on the measurement result of the thermistor 7. The heating time calculation means C4 calculates the heating time t1, which is the time required to raise the temperature to the driving temperature, based on the temperature detected by the temperature detection means C3 and a predetermined temperature (driving temperature) during image formation of the LED array 3. The heating time calculation means C4 in this embodiment calculates the heating time t1 for each of the exposure devices LHy to LHk of each color. The heating control means C5 controls the exposure heater control circuit D1 to heat the LED array 3. In this embodiment, the heating control means C5 turns on the exposure heater 6 until the temperature measured by the thermistor 7 reaches the drive temperature, and turns off the exposure heater 6 when the drive temperature is reached.

[0049] The adjustment means C6 includes a first adjustment means C6a, a second adjustment means C6b, an adjustment execution determination means C6c, an adjustment order setting means C6d, and an execution order interchange determination means C6e. The adjustment means C6 adjusts the image quality based on the detection result of the image for image quality adjustment. The first adjustment means C6a has a first separation adjustment means C6a1 and a first contact adjustment means C6a2, and performs a first adjustment, which is an image quality adjustment based on the detection result of the image detection sensor SN1, so-called high image quality adjustment. As an example of the first adjustment, the first adjustment means C6a adjusts the density of each color, adjusts the hue of multiple overlapping colors, and adjusts the position of each color image (adjusts misalignment).

[0050] The first adjustment unit C6a in the first embodiment performs the first adjustment when the exposure devices LHy to LHk have reached their operating temperature. That is, the image quality is adjusted when the temperatures of the exposure devices LHy to LHk have reached their operating temperature, heating has been completed, and the adverse effects of thermal expansion of the frame 1 have been eliminated. Therefore, the adverse effects of thermal expansion on the first adjustment are prevented more effectively than when the first adjustment is performed before heating is completed. Furthermore, as a result of the first adjustment by the first adjustment means C6a in Example 1, the density, color tone, and positional misalignment are adjusted, and when the job is executed by the job control means C1, the light intensity of the exposure devices LHy to LHk, the number and positions of the light-emitting elements that are turned on, and the timing at which they are turned on are adjusted.

[0051] The first spacing adjustment unit C6a1 in the first embodiment performs the first spacing adjustment in a state in which the secondary transfer roller T2b is separated from the intermediate transfer belt B (in a retracted state). In the first embodiment, examples of the first spacing adjustment include adjustment of the image detection sensor SN1 (sensitivity correction of the image detection sensor SN1) and adjustment of misalignment between the LED arrays 3 (adjustment of misalignment at joints). For example, in a copier U compatible with A3 paper, in the case where a configuration is adopted in which a plurality of A4-width LED arrays 3 are arranged in the main scanning direction, it is preferable to perform the first spacing adjustment to adjust misalignment between the LED arrays 3 at the boundary portions (joints) of the LED arrays 3 in the main scanning direction. Furthermore, the first contact adjustment unit C6a2 in the first embodiment performs the first contact adjustment while the secondary transfer roller T2b is in contact with the intermediate transfer belt B (contact state). In the first embodiment, examples of the first contact adjustment include adjusting the position of each color image (color registration adjustment), adjusting the density of each color image (gradation adjustment), and adjusting the color of each color image. Note that color registration adjustment and adjustment of misalignment at joints can be performed in the contact state, but they can also be performed in the retracted state. If the secondary transfer roller T2b is brought into contact with the intermediate transfer belt B after adjusting the position in the retracted state, the tension of the intermediate transfer belt B will change, and this change in tension may cause misalignment. Therefore, in the first embodiment, the image position adjustment is performed in the contact state, and it is desirable to adjust misalignment in the contact state. In addition, adjustments of density and color are less affected by changes in tension, and in the contact state, there is a risk that the secondary transfer roller T2b will become dirty with the image for adjusting image quality that is formed to adjust density, etc., so it is preferable to adjust density, etc. in the retracted state.

[0052] The second adjustment unit C6b has a second separation adjustment unit C6b1 and a second contact adjustment unit C6b2, and performs a second adjustment, so-called low-image-quality adjustment, which is an image quality adjustment that is not based on the detection results of the image detection sensor SN1. Examples of the second adjustment performed by the second adjustment unit C6b include forming a toner band to discharge deteriorated developer, idling the photoconductors PRy-PRk and the intermediate transfer belt B to remove discharge products adhering to the surfaces, driving the developing devices Gy-Gk in a non-developing state to agitate the developer therein, detecting the transfer resistance in the transfer areas Q3y-Q3k and Q4, and aligning the rotation phases of the four photoconductors PRy-PRk.

[0053] The second adjustment means C6b in the first embodiment performs the second adjustment even when the exposure apparatuses LHy to LHk have not yet reached their operating temperature. In particular, in the first embodiment, the second adjustment is performed while the exposure apparatuses LHy to LHk are being heated. Therefore, even if the temperature of the exposure apparatuses LHy to LHk has not yet reached their operating temperature and the adverse effects of thermal expansion of the frame 1 remain, the second adjustment is not significantly affected, and the second adjustment is therefore performed to prevent degradation in image quality, i.e., to adjust the image quality. Furthermore, as a result of the second adjustment by the second adjustment means C6b in Example 1, when executing a job, the job control means C1 does not particularly adjust the light intensity of the exposure devices LHy to LHk, the number and position of the light-emitting elements that are turned on, or the timing at which they are turned on.

[0054] The second separation adjustment unit C6b1 in the first embodiment performs the second separation adjustment in a state (retracted state) in which the secondary transfer roller T2b is separated from the intermediate transfer belt B. In the first embodiment, examples of the second separation adjustment include the discharge of the deteriorated developer, stirring in the developing devices Gy to Gk, and removal of discharge products. Discharge of the deteriorated developer and removal of discharge products are preferably performed in the retracted state because there is a risk that the secondary transfer roller T2b may become soiled with the developer or discharge products. Furthermore, the second contact adjustment unit C6b2 in the first embodiment performs the second contact adjustment in a state (contact state) in which the secondary transfer roller T2b is in contact with the intermediate transfer belt B. In the first embodiment, the detection of transfer resistance and phase adjustment described above are performed as an example of the second contact adjustment. Transfer resistance cannot be detected unless the secondary transfer roller T2b is in contact, and phase adjustment may result in a phase shift if performed in a retracted state and then returned to a contact state. Therefore, it is desirable to detect transfer resistance and perform phase adjustment in a contact state.

[0055] The adjustment execution determination means C6c determines whether or not to execute image quality adjustment. The adjustment execution determination means C6c determines whether or not to execute each of the first adjustment and the second adjustment. In the first embodiment, the conditions for executing each adjustment operation are determined in advance for each of the first separation adjustment, the first contact adjustment, the second separation adjustment, and the second contact adjustment. For example, the following conditions are defined for each adjustment operation: a large difference between the temperature and humidity at the time of the previous image quality adjustment and the current temperature and humidity; the time the copier U has been left unused (the cumulative time it has not been used) reaches a threshold; the time elapsed since the previous image quality adjustment reaches a threshold; the opening and closing of the maintenance door is detected; the printing mode is switched between color and black-and-white; parts are replaced; the cumulative number of rotations of the photoconductors PRy-PRk or the intermediate transfer belt B reaches a threshold; the adjustment operation is performed when the copier U is turned on; the cumulative number of printed sheets reaches a predetermined number (e.g., 5,000 sheets); the cumulative number of printed pixels reaches a predetermined value; a predetermined number of consecutive low-density images (e.g., 5% or less) (e.g., 1,000 sheets); etc. The adjustment execution determination unit C6c then determines whether the conditions for executing each adjustment operation are met. The execution conditions for the adjustment operations are not limited to those exemplified above and can be freely changed depending on the design and specifications.

[0056] The adjustment order setting unit C6d sets the adjustment order when there are multiple adjustment operations determined to be performed. In the first embodiment, when both image quality adjustment with the secondary transfer roller T2b separated from the intermediate transfer belt B and image quality adjustment with the secondary transfer roller T2b in contact with the intermediate transfer belt B are performed, the adjustment order is set so that image quality adjustment with the secondary transfer roller T2b in the separated state is performed first, followed by image quality adjustment with the secondary transfer roller T2b in the contact state. If image quality adjustment with the secondary transfer roller T2b in the separated state is performed later, an operation to move the secondary transfer roller T2b to the contact position (contact / separation switching operation) is required after the image quality adjustment with the secondary transfer roller T2b in the separated state is completed and before printing starts. In other words, the total time required until printing starts is extended by the time required for the contact / separation switching operation. Therefore, the overall time can be shortened by performing image quality adjustment with the secondary transfer roller T2b in the contact state later. Furthermore, the adjustment order setting means C6d in the first embodiment sets the adjustment order so that when low-quality adjustment (second adjustment) and high-quality adjustment (first adjustment) are performed, low-quality adjustment is performed first. If high-quality adjustment is performed first, errors may occur in the results of the high-quality adjustment due to contamination with discharged developer or discharge products in the low-quality adjustment performed later, or image quality may deteriorate if transfer resistance adjustment or phase alignment is performed after high-quality adjustment. Therefore, it is preferable to perform low-quality adjustment first and high-quality adjustment later. Therefore, the adjustment order setting means C6d of Example 1 sets the adjustment order for the four types of adjustment operations, namely, first separation adjustment, first contact adjustment, second separation adjustment, and second contact adjustment, so that the adjustments are performed in the order of second separation adjustment, first separation adjustment, second contact adjustment, and first contact adjustment.

[0057] The execution order exchange determination means C6e exchanges the adjustment order set by the adjustment order setting means C6d based on the heating time t1, the period ta of the second separation adjustment, the period tb of the second contact adjustment, and the movement time tc (the time for the contact / separation switching operation) for the secondary transfer roller T2b to move between the contact position and the separation position. As an example, when the second separation adjustment, the first separation adjustment, and the second contact adjustment are executed in this order, if the sum (ta+tb+tc×2) of the period ta of the second separation adjustment, the period tb of the second contact adjustment, and the time tc×2 for the switching operation is shorter than the heating time t1, the adjustment order is exchanged so that the second separation adjustment, (the switching operation,) the second contact adjustment, (the switching operation,) the first separation adjustment are executed in this order. Furthermore, when the first separation adjustment and the second contact adjustment are performed, if the sum (tb+tc) of the period tb of the second contact adjustment and the time tc of the switching operation is shorter than the heating time t1, the order of execution of the first separation adjustment and the second contact adjustment is reversed so that the second contact adjustment, (the switching operation), and the first separation adjustment are performed in that order.

[0058] FIG. 5 is an explanatory diagram for comparing the adjusting operation patterns of the first embodiment with the conventional configuration, and is an explanatory diagram for patterns No. 1 to No. 8. FIG. 6 is a continuation of FIG. 5 and is an explanatory diagram of patterns No. 9-1 to No. 13-2. FIG. 7 is a continuation of FIG. 6 and is an explanatory diagram of patterns No. 14 to No. 15-2. Therefore, in the adjusting means C6 of the first embodiment, when heating of the exposure devices LHy to LHk and the second spacing adjustment are performed, the second spacing adjustment is performed in parallel with the heating, as shown in patterns Nos. 4 to 7 and 12 to 15 in Figures 5 to 7. Therefore, the period ta during which the second spacing adjustment (second adjustment) is performed and the heating period (heating time t1) overlap.

[0059] Furthermore, when the first separation adjustment or the first contact adjustment is performed after the second separation adjustment, as shown in patterns 6, 7, and 12 to 15, the first separation adjustment or the first contact adjustment is performed after the second separation adjustment and heating are completed. At this time, if the second contact adjustment is also performed, the total time of the period ta of the second separation adjustment, the period tb of the second contact adjustment, and the time tc of the two switching operations is compared to the heating time t1. If t1>ta+tb+tc×2, the second contact adjustment is switched so that it is performed before the first separation adjustment, as shown in patterns 7, 13-2, and 15-1. Therefore, the second separation adjustment and the second contact adjustment are performed during heating, and the first separation adjustment and the first contact adjustment are performed after heating.

[0060] If t1≦ta+tb+tc×2, the second contact adjustment and the first separation adjustment are not switched, and the image quality adjustment operation is performed, as shown in patterns 13-1 and 15-2. In this case, the second separation adjustment is performed during heating, and after heating is completed, the first separation adjustment, second contact adjustment, and first contact adjustment are performed. Furthermore, if the second contact adjustment is performed without the first separation adjustment or the first contact adjustment being performed after the second separation adjustment, the second separation adjustment and the second contact adjustment are performed in sequence in parallel during heating, as shown in pattern No. 5.

[0061] If the second separation adjustment or the second contact adjustment is not performed and the first separation adjustment or the first contact adjustment is performed, that is, if the second adjustment is not performed and only the first adjustment is performed, the first adjustment is performed after heating is completed, as shown in patterns No. 2, 8, and 10. When the second separation adjustment is not performed and the first separation adjustment and the second contact adjustment are performed, as shown in patterns 9 and 11, the total time of the period tb of the second contact adjustment and the time tc of the switching operation is compared to the heating time t1. If t1>tb+tc, then as shown in patterns 9-1 and 11-1, the second contact adjustment is performed before the first separation adjustment. Therefore, the second contact adjustment is performed during heating, and after heating is completed, the first separation adjustment and the first contact adjustment are performed. Note that if t1≦tb+tc, then as shown in patterns 9-2 and 11-2, the second contact adjustment and the first separation adjustment are not switched, and after heating is completed, the adjustment operations are performed in order, starting with the first separation adjustment.

[0062] When the second separation adjustment and the first separation adjustment are not performed and only the second contact adjustment and the first contact adjustment are performed, that is, when the image quality adjustment in the retracted state is not performed and only the image quality adjustment in the contact state is performed, the second contact adjustment is performed in parallel with the heating, and the first contact adjustment is performed after the heating is completed, as shown in patterns No. 1 and 3. In FIG. 4, a contact / separation control means C7 moves the secondary transfer roller T2b between a contact position where it contacts the intermediate transfer belt B and a separation position where it is separated from the intermediate transfer belt B via a separation control circuit D2.

[0063] (Explanation of the flow chart of Example 1) Next, the control flow in the copying machine U of the first embodiment will be explained using a flow chart. (Explanation of the flow chart of the image quality adjustment process) FIG. 8 is a flowchart of the image quality adjustment process according to the first embodiment. 9A is a flowchart continuing from ST14 in FIG. 8, FIG. 9B is a flowchart continuing from ST13 in FIG. 8, and FIG. 9C is a flowchart continuing from ST12 in FIG. FIG. 10 is a flowchart continuing from ST9 in FIG. 8 to 10 are performed in accordance with a program stored in the control unit C. This processing is performed in parallel with various other processing of the copier U. The flowcharts shown in FIGS. 8 to 10 start when the copier U is turned on.

[0064] 8, it is determined whether or not a job, which is an image forming operation, has started. If yes (Y), the process proceeds to ST2. If no (N), ST1 is repeated. In ST2, the heating time t1 is calculated, and then the process proceeds to ST3. In ST3, it is determined whether the conditions for performing the image quality adjustment, i.e., the first adjustment or the second adjustment, are met. If the answer is no (N), proceed to ST4, and if the answer is yes (Y), proceed to ST7. In ST4, it is determined whether or not there is a heating time t1, that is, whether or not the heating time t1 is 0. If yes (Y), proceed to ST5, and if no (N), proceed to ST72. In ST5, the exposure tools LHy to LHk are heated, and then the process proceeds to ST6. In ST6, it is determined whether or not heating has been completed. If yes (Y), proceed to ST72; if no (N), repeat ST6.

[0065] In ST7, it is determined whether or not there is a heating time t1, that is, whether or not the heating time t1 is 0. If no (N), proceed to ST8, and if yes (Y), proceed to ST9. In ST8, the image quality adjustment is performed by setting the order of the second separation adjustment, the first separation adjustment, the second contact adjustment, and the first contact adjustment, and then proceeding to ST71. In ST9, it is determined whether or not the second separation adjustment is to be performed. If yes (Y), proceed to ST10, and if no (N), proceed to ST51. In ST10, it is determined whether the period ta of the second separation adjustment reaches the heating time t1. If yes (Y), proceed to ST11, and if no (N), proceed to ST12. In ST11, the image quality adjustment (first adjustment and second adjustment) is performed in parallel with heating. ST11 is the situation shown in pattern No. 15-2, where the second distance adjustment is performed in parallel with heating, heating is completed during the second distance adjustment, and adjustment processes after the second distance adjustment are performed in order. Then, the process proceeds to ST71.

[0066] In ST12, it is determined whether or not the second contact adjustment is to be performed. If yes (Y), proceed to ST13, and if no (N), proceed to ST41. In ST13, it is determined whether or not the first separation adjustment is to be performed. If yes (Y), the process proceeds to ST14, and if no (N), the process proceeds to ST31. In ST14, it is determined whether the heating time t1 reaches the sum of the period ta of the second separation adjustment, the period tb of the second contact adjustment, and the time tc of two switching operations. If the answer is yes (Y), proceed to ST15; if the answer is no (N), proceed to ST21. In ST15, the execution order is changed so that the second separation adjustment and the second contact adjustment are executed in parallel with the heating, as shown in patterns No. 13-2 and 15-1, and then the process proceeds to ST16. In ST16, it is determined whether or not heating is complete. If yes (Y), proceed to ST17. If no (N), repeat ST16. In ST17, if there is any remaining adjustment operation after the completion of heating, it is executed. That is, if the first adjustment (first separation adjustment and / or first contact adjustment) is set to be executed, the first adjustment is executed. Then, the process proceeds to ST71.

[0067] In ST21 of Fig. 9A, the second spacing adjustment is performed in parallel with heating as shown in pattern No. 13-1, and then the process proceeds to ST22. In ST22, it is determined whether or not heating has been completed. If yes (Y), proceed to ST23; if no (N), repeat ST22. In ST23, the remaining image quality adjustments that have been set (first separation adjustment, second contact adjustment, and first contact adjustment) are performed, and then the process proceeds to ST71.

[0068] In ST31 of Fig. 9B, the second separation adjustment and the second contact adjustment are performed in sequence in parallel with heating, as shown in patterns Nos. 5 and 7. Even if heating is completed midway through the second separation adjustment or the second contact adjustment, there is no problem because there is almost no adverse effect from incomplete heating of the second adjustment. Then, the process proceeds to ST32. In ST32, it is determined whether the second adjustment and heating are completed. If yes (Y), proceed to ST33; if no (N), repeat ST32. In ST33, the remaining image quality adjustments that have been set (first separation adjustment, second contact adjustment, and first contact adjustment) are performed, and then the process proceeds to ST71.

[0069] In ST41 of Fig. 9C, the second spacing adjustment is performed in parallel with heating as shown in patterns 4, 6, 12, and 14. Then, the process proceeds to ST42. In ST42, it is determined whether or not heating has been completed. If yes (Y), proceed to ST43; if no (N), repeat ST42. In ST43, the remaining image quality adjustments that have been set (first separation adjustment, second contact adjustment, and first contact adjustment) are performed, and then the process proceeds to ST71.

[0070] In ST51 of Fig. 10, it is determined whether or not the second contact adjustment is to be performed. If the answer is yes (Y), the situation corresponds to pattern Nos. 1, 3, 9, and 11, and the process proceeds to ST52. If the answer is no (N), the situation corresponds to pattern Nos. 2, 8, and 10, and the process proceeds to ST57. In ST52, it is determined whether or not the first separation adjustment is to be performed. If the answer is yes (Y), the situation corresponds to pattern Nos. 9 and 11, and the process proceeds to ST53. If the answer is no (N), the situation corresponds to pattern Nos. 1 and 3, and the process proceeds to ST61. In ST53, it is determined whether the heating time t1 reaches the sum of the period tb of the second contact adjustment and the time tc of the switching operation. If the answer is yes (Y), the situation corresponds to pattern No. 9-1 or 11-1, and the process proceeds to ST54. If the answer is no (N), the situation corresponds to pattern No. 9-2 or 11-2, and the process proceeds to ST57.

[0071] In ST54, the execution order is changed so that the second contact adjustment is performed in parallel with the heating, as shown in patterns No. 9-1 and 11-1, and the process then proceeds to ST55. In ST55, it is determined whether or not heating has been completed. If yes (Y), proceed to ST56, and if no (N), repeat ST55. In ST56, the remaining set first image quality adjustments (first separation adjustments and first contact adjustments) are performed, and then the process proceeds to ST71. In ST57, the execution order is not changed and it is determined whether or not heating is completed. If yes (Y), proceed to ST58, and if no (N), repeat ST57. In ST58, the image quality adjustments (first separation adjustment, second contact adjustment, and first contact adjustment) are performed in the set execution order as shown in patterns Nos. 2, 8, 9-2, 10, and 11-2, and then the process proceeds to ST71.

[0072] In ST61, the contact second adjustment is performed in parallel with the heating as shown in patterns No. 1 and 3. Then, the process proceeds to ST62. In ST62, it is determined whether or not heating has been completed. If yes (Y), proceed to ST63; if no (N), repeat ST62. In ST63, it is determined whether or not the first contact adjustment is to be performed. If yes (Y), proceed to ST64. If no (N), the situation corresponds to pattern No. 1, and proceed to ST71. In ST64, the first contact adjustment is performed as shown in Pattern No. 3, and the process proceeds to ST71. 8, it is determined whether or not the image quality adjustment is complete. If yes (Y), the process proceeds to ST72, and if no (N), ST71 is repeated. In ST72, the printing operation is executed (started), and when the printing operation is completed, the process returns to ST1.

[0073] (Function of Example 1) In the copier U of Example 1 having the above configuration, if a second adjustment, such as the discharge of deteriorated developer, is performed without the completion of heating of the exposure devices LHy to LHk, it is performed in parallel with the heating of the exposure devices LHy to LHk. On the other hand, a first adjustment, such as image density adjustment or image position adjustment, which is likely to be affected by errors if the heating of the exposure devices LHy to LHk is not completed, is performed after the heating is completed. In the prior art, the heating of the exposure devices and the image quality adjustment are performed separately. As shown in the prior art of FIGS. 5 to 7, the image quality adjustment is performed after the heating of the exposure devices is completed. Therefore, the prior art had a problem of increasing the overall time required before printing could begin. In contrast, in Example 1, the image quality adjustment, which can be performed without causing any problems even if it is performed during heating, is performed in parallel with the heating. Therefore, compared to the prior art in which the image quality adjustment of the image forming means is performed after the heating is completed, the time required before printing can begin is shortened and productivity is improved.

[0074] Furthermore, in the first embodiment, the first adjustment (high image quality adjustment) is performed after the second adjustment (low image quality adjustment), and degradation of image quality is suppressed compared to when the high image quality adjustment is performed first. Furthermore, in the first embodiment, image quality adjustment is performed with priority given to the state in which the secondary transfer roller T2b is separated from the intermediate transfer belt B, and then image quality adjustment is performed with the secondary transfer roller T2b in contact with the intermediate transfer belt B. Therefore, compared to the case in which image quality adjustment is performed later with the secondary transfer roller T2b in a separated state, there is no need to bring the secondary transfer roller T2b into contact with the intermediate transfer belt B after image quality adjustment, and it is possible to move quickly to the printing operation. This reduces the overall time required to start printing, improving productivity.

[0075] In addition, in the first embodiment, when the first separation adjustment and the second contact adjustment are performed, and even if the second contact adjustment is performed during heating, if the second contact adjustment is completed before the heating is completed, that is, if the heating time t1 is sufficiently long, the execution order of the first separation adjustment and the second contact adjustment is reversed as shown in patterns No. 9-1, 11-1, 13-2, and 15-1. Therefore, productivity is further improved compared to when the reverse is not performed.

[0076] (Example of change) Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments and various modifications can be made within the scope of the gist of the present invention as set forth in the claims. Modifications (H01) to (H04) of the present invention are exemplified below. (H01) In the above embodiment, a copier U was used as an example of an image forming device, but this is not limited to this and it is also possible to configure it as, for example, a printer, a fax machine, or a multifunction device having multiple or all of these functions.

[0077] (H02) In the above embodiment, a configuration in which four color developers are used as the copier U is exemplified, but this is not limited to this and the present invention is also applicable to, for example, a monochrome image forming apparatus or a multi-color image forming apparatus with three or less colors or five or more colors. (H03) In the above embodiment, an endless intermediate transfer belt B was used as an example of an image holding means, but this is not limiting. For example, the present invention can be applied to a cylindrical intermediate transfer drum, a photosensitive drum, or a photosensitive belt. It can also be applied to a configuration in which an image is recorded directly from a photosensitive drum onto recording paper S without using an intermediate transfer body.

[0078] (H04) In the above embodiment, it is preferable to perform the second adjustment prior to the first adjustment, but it is also possible to perform the first adjustment prior to the second adjustment. Also, it is preferable to perform the image quality adjustment in the retracted state prior to the image quality adjustment in the contact state, but it is also possible to perform the image quality adjustment in the contact state first.

[0079] (Addendum) (((1))) an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; a detection means for detecting the image held by the image holding means; an adjustment means for performing a first adjustment for adjusting the image quality of an image based on the detection result of the detection means, and a second adjustment for adjusting the image quality not based on the detection result of the detection means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising: (((2))) an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjustment means for performing a first adjustment for adjusting the image quality when the temperature of the image forming means reaches a predetermined temperature, and a second adjustment for adjusting the image quality regardless of the temperature of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising: (((3))) an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjustment means for performing a first adjustment that involves adjusting control of the image forming means and a second adjustment that does not involve adjusting control of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising: (((4))) the heating means has a plurality of light-emitting elements that output light to form an image, and the light-emitting elements are arranged in a line along the scanning direction of the image, and are heated by heat generated by the exposure means when current is passed through a drive circuit that drives the exposure means, or by heat generated by a heater that heats the exposure means; The image forming apparatus according to any one of ((1))) to ((3))). (((5))) the adjusting means for performing the first adjustment for adjusting the density of an image formed by the image forming means; The image forming apparatus according to any one of ((1))) to ((4))) is provided with: (((6))) the adjusting means for performing the first adjustment to adjust the position of the image formed by the image forming means; The image forming apparatus according to any one of ((1))) to ((5))) is provided with: (((7))) a developing means for developing the image formed on the image holding means by the image forming means with a developer; the second adjustment for discharging the developer from the developing means to the image holding means; The image forming apparatus according to any one of ((1))) to (((6))) is provided with: (((8))) the adjusting means for, when the first adjustment and the second adjustment are executed, executing the second adjustment and then the first adjustment in that order, and for heating the image forming means during the execution of the second adjustment; The image forming apparatus according to any one of ((1))) to (((7))) is provided with: (((9))) the adjusting means for starting the first adjustment after the second adjustment is finished and heating is completed; The image forming apparatus according to any one of ((1))) to ((8))) is provided with: (((10))) a transfer means for transferring an image from the image holding means to a medium, the transfer means being movable between a contact position where it contacts the image holding means and a separation position where it is separated from the image holding means; an adjusting unit that, when at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the separation position and at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the contact position, prioritizes performing the adjustment when the transfer unit is moved to the separation position; The image forming apparatus according to any one of ((1))) to (((9))) is provided with: (((11))) when the first adjustment is performed with the transfer means moved to the separation position and the second adjustment is performed with the transfer means moved to the contact position, and when a time obtained by adding a period of the second adjustment to a moving time of the transfer means moving between the contact position and the separation position is shorter than a length of the heating period, the adjustment means reverses the order of performing the first adjustment and the second adjustment and performs the second adjustment first; The image forming apparatus according to (((10))) is characterized by comprising:

[0080] According to the image forming apparatus of (((1))), productivity can be improved compared to when the image quality adjustment of the image forming means is performed after the heating is completed. According to the image forming apparatus of (((2))), productivity can be improved compared to when the image quality adjustment of the image forming means is performed after the heating is completed. According to the image forming apparatus of (((3))), productivity can be improved compared to when the image quality adjustment of the image forming means is performed after the heating is completed. According to the image forming apparatus of (((4))), heating can be achieved by energizing the drive circuit of the exposure means in which a plurality of light emitting elements are arranged in a line along the operation direction, or by heat generation from the heating zone. According to the image forming apparatus of (((5))), the density of the image can be adjusted by the first adjustment. According to the image forming apparatus of (((6))), the position of the image can be adjusted by the first adjustment. According to the image forming apparatus of (((7))), the developer that has deteriorated in the second adjustment is discharged, and the image quality can be adjusted. According to the image forming apparatus of (((8))), it is possible to suppress deterioration in image quality compared to when the second adjustment is performed after the first adjustment. According to the image forming apparatus of (((9))), it is possible to suppress the adverse effect of incomplete heating of the image forming means on the first adjustment, compared to when the first adjustment is performed before the heating is completed. According to the image forming apparatus of (((10))), it is possible to move quickly to image forming operation after the adjustment is completed, compared to when the adjustment is first performed while the transfer means is moved to the contact position, thereby improving productivity. According to the image forming apparatus of (((11))), the time required for image forming operation can be shortened and productivity can be improved compared to when the order of execution of the first adjustment and the second adjustment is not switched. [Explanation of symbols]

[0081] 6...Heating means, B...image holding means, C5...heating control means, C6...adjustment means, Gy, Gm, Gc, Gk...developing means, LHy, LHm, LHc, LHk...image forming means, S...medium, SN1...detection means, ta, tb...period during which the second adjustment is performed, T2: Transfer means, U...Image forming device.

Claims

1. an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; a detection means for detecting the image held by the image holding means; an adjustment means for performing a first adjustment for adjusting the image quality of an image based on the detection result of the detection means, and a second adjustment for adjusting the image quality not based on the detection result of the detection means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising:

2. an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjusting means for performing a first adjustment for adjusting the image quality when the temperature of the image forming means reaches a predetermined temperature, and a second adjustment for adjusting the image quality regardless of the temperature of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising:

3. an image forming means for forming an image; a heating means for heating the image forming means; an image holding means for holding an image formed by the image forming means; an adjustment means for performing a first adjustment that involves adjusting control of the image forming means and a second adjustment that does not involve adjusting control of the image forming means; a heating control means for controlling the heating means to heat the image forming means to a predetermined temperature, the heating control means performing heating during a period overlapping with a period during which the second adjustment is performed; An image forming apparatus comprising:

4. the heating means has a plurality of light-emitting elements that output light to form an image, and the light-emitting elements are arranged in a line along the scanning direction of the image, and are heated by heat generated by the exposure means when current is passed through a drive circuit that drives the exposure means, or by heat generated by a heater that heats the exposure means; 4. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the adjusting means for performing the first adjustment for adjusting the density of the image formed by the image forming means; 4. The image forming apparatus according to claim 1, further comprising:

6. the adjusting means for performing the first adjustment to adjust the position of the image formed by the image forming means; 4. The image forming apparatus according to claim 1, further comprising:

7. a developing means for developing the image formed on the image holding means by the image forming means with a developer; the second adjustment for discharging the developer from the developing means to the image carrying means; 4. The image forming apparatus according to claim 1, further comprising:

8. the adjusting means for, when the first adjustment and the second adjustment are executed, executing the second adjustment and then the first adjustment in that order, and for heating the image forming means during the execution of the second adjustment; 4. The image forming apparatus according to claim 1, further comprising:

9. the adjusting means for starting the first adjustment after the second adjustment is finished and heating is completed; 9. The image forming apparatus according to claim 8, further comprising:

10. a transfer means for transferring an image from the image holding means to a medium, the transfer means being movable between a contact position where it contacts the image holding means and a separation position where it is separated from the image holding means; an adjusting unit that, when at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the separation position and at least one of the first adjustment and the second adjustment is performed when the transfer unit is moved to the contact position, prioritizes performing the adjustment when the transfer unit is moved to the separation position; 4. The image forming apparatus according to claim 1, further comprising:

11. an adjustment unit that switches the order of execution of the first adjustment and the second adjustment and executes the second adjustment first when the time obtained by adding the period of the second adjustment to the moving time of the transfer unit between the contact position and the separating position is shorter than the length of the heating period, in a case where the first adjustment is executed with the transfer unit moved to the separated position and the second adjustment is executed with the transfer unit moved to the contact position, 11. The image forming apparatus according to claim 10, further comprising:

Images