JP4622206B2 - Color image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color image forming apparatus such as a color printer or a color copying machine, and in particular, in a so-called tandem type color image forming apparatus provided with a plurality of image forming units that form images of different colors. The present invention relates to a registration control technique for controlling registration (hereinafter, also simply referred to as “registration”), which is an image forming position of each color image formed by a forming unit.
[0002]
[Patent Document 1]
Japanese Patent Laid-Open No. 1-142274
[Patent Document 2]
Japanese Patent Laid-Open No. 1-142680
[Patent Document 3]
Japanese Patent Laid-Open No. 1-183676
[Patent Document 4]
Japanese Patent No. 2625130
[Patent Document 5]
Japanese Patent No. 2921856
[0003]
[Prior art]
Conventionally, as a so-called tandem type color image forming apparatus provided with a plurality of image forming units of this type, there is one as shown in FIG. As shown in FIG. 31, the tandem type color image forming apparatus includes four image forming units 100Y, 100M, 100C, and 100K that form toner images of different colors such as yellow, magenta, cyan, and black. These image forming units 100Y, 100M, 100C, and 100K are arranged in parallel at regular intervals along the horizontal direction. The four image forming units 100Y, 100M, 100C, and 100K are configured in the same manner except that the color of the toner image to be formed is different, and the surface of the photosensitive drum 101 is uniformly formed by the contact-type charging device 102. Then, the exposure device 103 performs image exposure on the surface of the photosensitive drum 101 to form an electrostatic latent image corresponding to the image information of each color. The electrostatic latent image formed on the surface of the photosensitive drum 101 is visualized by a corresponding color developing device 104 to become a toner image, and the toner image is transferred to an intermediate transfer belt by a charger 105 for primary transfer. Multiple images are sequentially transferred onto the 106. The toner remaining on the surface of the photosensitive drum 101 is removed by the cleaning device 107 to prepare for the next image forming process.
[0004]
The intermediate transfer belt 106 is disposed below the four image forming units 100Y, 100M, 100C, and 100K, and the rotation speed of the photosensitive drum 101 is determined by a plurality of rollers 108 to 111 including a driving roller. It is designed to circulate at an equal speed. The toner images of yellow, magenta, cyan, and black, which are sequentially transferred onto the intermediate transfer belt 106 in multiple layers, are transferred to the surface of the intermediate transfer belt 106 at the secondary transfer position provided below the intermediate transfer belt 106. Are transferred all together onto a recording sheet 113 fed at a predetermined timing by a secondary transfer roll 112 in contact with the recording medium. Thereafter, the recording sheet 113 is transported to the fixing device 114, subjected to a fixing process with heat and pressure by the fixing device 114, and discharged to the outside of the device to form a full-color or monochrome image.
[0005]
By the way, in such a tandem type color image forming apparatus, a plurality of image forming units are controlled by controlling an image forming position of each color image formed by the plurality of image forming units 100Y, 100M, 100C, and 100K, that is, registration. A registration control technique is employed in which the registration of the images of the respective colors formed at 100Y, 100M, 100C, and 100K is matched with each other with high accuracy.
[0006]
Examples of an image forming apparatus employing this registration control technique are disclosed in Japanese Patent Application Laid-Open Nos. 1-142474, 1-142680, 1-183676, and the like. 32, a predetermined image position recognition pattern 120 is formed on the photosensitive drum 101 by the ROS 103 of each of the image forming units 100Y, 100M, 100C, and 100K. The image position recognition pattern 120 of each color formed on the upper surface is sequentially primary-transferred onto the intermediate transfer belt 106, and is sampled by the CCD 121 disposed on the downstream side of the final image forming unit 100K. The image position recognition pattern 12 for each color determined in advance in the positional relationship. The positional relationship when it is assumed that the color shift was not in, detects which there is only a difference, the registration shift of each color from the detection data (hereinafter. Referred to as "misregistration") is calculated amount. In the image forming apparatus, there is a method of providing a high-quality image with little misregistration by correcting the writing timing of the ROS 103 of each of the image forming units 100Y, 100M, 100C, and 100K or the position of the components of the optical system. Proposed.
[0007]
The image position recognition pattern 120 of each color transferred onto the intermediate transfer belt 106 is removed by a cleaning device 115 that cleans the surface of the intermediate transfer belt 106.
[0008]
As a technique related to this registration control apparatus, for example, there are those disclosed in Japanese Patent Application Laid-Open Nos. 1-142274, 1-142680, 1-183676, and the like.
[0009]
Further, as a technique for correcting the deterioration of the color registration misalignment amount caused by the temperature rise in the apparatus, those disclosed in Japanese Patent Nos. 2625130 and 2921856 have already been proposed.
[0010]
The techniques disclosed in these Patent Nos. 2625130 and 2921856 are such that when the temperature rise in the machine changes by a predetermined temperature from the time of power-on or from the execution of the regicon, or from the temperature at which the previous regicon was carried out. When the temperature changes by a predetermined temperature, the regicon sequence is operated.
[0011]
More specifically, the image forming apparatus according to Japanese Patent No. 2525130 transfers a plurality of image stations each having an image carrier and each image formed on the plurality of image carriers at a transfer position. Formed by the plurality of image stations formed by the plurality of image stations and read by each of the registration mark images transferred onto the movable body, and formed by the plurality of image stations based on the reading result of the reading means. A correction means for correcting a positional deviation between the images, a temperature detection means for detecting the temperature inside the apparatus, and the plurality of image stations form the registration mark images so that the registration mark images are formed on the movable body. The reading means reads each registration mark image transferred onto the moving body, and the correction means Based on the read result is obtained by configured with, and control means for controlling on the basis of an output of said temperature detecting means to execute the registration correction sequence for the correction operation.
[0012]
Further, the color image forming apparatus according to the above-mentioned Japanese Patent Publication No. 2921856 is arranged with an endless conveying means for conveying a transfer material, and a predetermined color along the moving direction of the endless conveying means, and different colors for the transfer material. In a color image forming apparatus having a plurality of image recording means for sequentially recording the images, a temperature detecting means for detecting the temperature inside the apparatus, and each time the temperature detected by the temperature detecting means rises by a predetermined temperature A control unit that forms a detection pattern corresponding to each color on the endless conveyance unit by the image forming unit, a pattern detection unit that detects the detection pattern, and a position of each color based on a detection result by the pattern detection unit And a correction processing unit that calculates a shift amount and corrects the shift amount of each color.
[0013]
On the other hand, in order to correct the deterioration of the color registration misalignment due to the temperature rise in the machine, as disclosed in Japanese Patent Laid-Open No. 1-96665, the current temperature based on the lowest temperature in actual use in the machine. A technique for controlling the writing timing in the sub-scanning direction based only on the difference between the two has already been proposed.
[0014]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, in the case of the technique disclosed in the above-mentioned Japanese Patent Nos. 2625130 and 2921856, etc., the execution of the resist correction sequence is controlled based on the output of the temperature detection means, or the temperature inside the apparatus Each time the temperature detected by the temperature detecting means for detecting the temperature rises by a predetermined temperature, the detection pattern is formed by a plurality of image forming means, and the detection pattern is detected and corrected. Is.
[0015]
However, in the above-described image forming apparatus, the temperature rise in the apparatus is not uniform depending on the frequency of the image forming operation and the content of the image forming operation to be executed, and the change characteristic of the color registration deviation with respect to the temperature in the apparatus is linear. Therefore, if the registration correction sequence is controlled based on the output of the temperature detection means or the color registration misalignment correction operation is performed every time the temperature inside the apparatus rises by a predetermined temperature, When the pattern formation or detection operation is performed unnecessarily, and the image formation operation is impossible due to the regicon sequence operation, the frequency of occurrence of so-called downtime, the toner consumption for forming the regicon patch, Alternatively, there is a problem that an unnecessary increase in the load on the cleaning member and the waste toner collection capacity is caused.
[0016]
In the case of the technique disclosed in the above Japanese Patent Laid-Open No. 1-96665, the writing timing in the sub-scanning direction is controlled based only on the difference from the current temperature with reference to the lowest temperature in actual use in the machine. However, because the temperature rise in the machine is not uniform and the change characteristic of the registration deviation with respect to the temperature in the machine is not linear, the amount of color registration deviation caused by the temperature rise in the machine Has a problem that it cannot be corrected sufficiently.
[0017]
Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to predict and correct a color registration shift caused by a temperature rise in the apparatus body. Registration misalignment can be sufficiently corrected, and image forming operation is impossible. So-called downtime is reduced, toner consumption for forming a registration patch is reduced, or load on the cleaning member is reduced. An object of the present invention is to provide a color image forming apparatus capable of reducing the collection capacity.
[0018]
Further, another object of the present invention is that if the toner consumption for forming the downtime, the registration control patch, or the load on the cleaning member is the same as that of the conventional apparatus, the correction accuracy of the registration control is improved. An object of the present invention is to provide a color image forming apparatus that can be improved.
[0019]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention described in claim 1 includes a plurality of image forming units that form images having different colors, and images having different colors formed by the plurality of image forming units. In a color image forming apparatus for forming a color image by transferring it onto a recording medium directly or via an intermediate transfer member, a temperature detecting means for detecting the temperature in the color image forming apparatus main body, and the temperature detecting means Prediction correction means for predicting and correcting color registration misalignment amounts in the plurality of image forming units based on the temperature in the apparatus main body detected by
The color registration misalignment detection pattern formed by each image forming unit is transferred onto the same pattern detection member, and the color registration misalignment detection pattern transferred onto the pattern detection member is detected, and the color is detected. A registration error correction operation executing means for executing a registration error correction operation, wherein the prediction correction means performs at least one color registration error amount while the registration error correction operation is executed by the registration error correction operation execution means. While performing the prediction correction operation,
The prediction correction means uses the temperature in the apparatus body when the registration error correction operation is executed by the registration error correction operation execution means as a reference temperature, Absolute temperature in the device body And the temperature difference between the allowable maximum registration error amount and the temperature at which the registration error occurs is stored in advance. Temperature parameter Execute prediction correction according to the reference temperature using the table Condition temperature Set
The temperature in the apparatus main body detected by the temperature detecting means is the reference temperature. Each time the temperature set as the condition temperature for executing the prediction correction is reached This is configured to execute the prediction correction operation.
[0020]
It should be noted that the color registration misalignment detection pattern does not naturally form the color registration misalignment amount predictive correction.
[0021]
Here, as the “pattern detection member”, for example, an intermediate transfer body on which an image formed by each image forming unit is primarily transferred is used. However, the present invention is not limited to this, and a recording medium is used. It may be a recording medium conveying member such as a belt to be conveyed, or a transfer member for finally transferring a plurality of images transferred onto the intermediate transfer member in a multiple manner onto the recording medium.
[0028]
Here, the “registration misalignment correction operation” means an operation of forming a registration misalignment detection pattern, detecting the registration misalignment detection pattern, and correcting the registration misalignment.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0044]
Embodiment 1
FIG. 2 is a schematic configuration diagram showing a tandem type digital color printer as an image forming apparatus according to Embodiment 1 of the present invention. The tandem type digital color printer includes an image reading device, and functions as a full-color copying machine. The digital color printer may of course form an image based on image data output from a personal computer (not shown) without including an image reading device. Further, the digital color printer may have a function as a facsimile.
[0045]
In FIG. 2, reference numeral 1 denotes a main body of a tandem type digital color printer (color image forming apparatus). The digital color printer main body 1 is an image reading apparatus that reads an image of a document 2 at an upper portion on one end side thereof. (IIT: Image Input Terminal) 4, and the digital color printer main body 1 has image data output from the image reading device 4, a personal computer (not shown) or the like, or a telephone line or a LAN. The image processing apparatus (IPS: Image Processing System) 12 that performs predetermined image processing on the image data that is sent and the image output based on the image data that has been subjected to predetermined image processing by the image processing apparatus 12 Image output device (IOT: Image Output Te) minal) 100 and are disposed.
[0046]
Inside the digital color printer main body 1, image forming units 13K for black (K), yellow (Y), magenta (M), and cyan (C) are provided as image forming units constituting the image output apparatus 100. 13Y, 13M, and 13C are arranged at regular intervals along the horizontal direction. Further, below the four image forming units 13K, 13Y, 13M, and 13C, an intermediate transfer member serving as an intermediate transfer body that transfers toner images of respective colors sequentially formed by these image forming units in a state of being superimposed on each other. The transfer belt 25 is disposed so as to be rotatable along the arrow direction. The toner images of each color transferred onto the intermediate transfer belt 25 in a multiple manner are collectively transferred onto a recording paper 34 as a recording medium fed from a paper feed tray 39 or the like, and then a fixing unit 37. Is fixed on the recording paper 34 and discharged to the outside.
[0047]
In the embodiment shown in FIG. 2, the image output apparatus 100 has black (K), yellow (Y), magenta (M), cyan (C) formed by the image forming units 13K, 13Y, 13M, and 13C. ) Are first transferred in a state where they are superimposed on the intermediate transfer belt 25 and then secondarily transferred from the intermediate transfer belt 25 onto the recording paper 34 to form a color image. However, the present invention is not limited to this. As shown in FIG. 30, black (K) and yellow (Y) formed by the image forming units 13K, 13Y, 13M, and 13C are used. ), Magenta (M), and cyan (C) toner images are transferred in a state of being superimposed on the recording paper 34 conveyed by the paper conveying belt 25 ′ as a recording medium conveying member. Of course, the present invention can be applied to a configuration in which a color image is formed by copying. The order of the colors of the image forming units 13K, 13Y, 13M, and 13C is not limited to the order of black (K), yellow (Y), magenta (M), and cyan (C). ), Magenta (M), cyan (C), black (K), and the like.
[0048]
FIG. 3 shows in more detail the configuration of the tandem type digital color printer as the image forming apparatus according to Embodiment 1 of the present invention.
[0049]
Here, the configuration of the present invention will be described using a tandem type digital color printer, but the present invention is also effective in a color copying machine / facsimile. The same applies to the following embodiments.
[0050]
In FIG. 3, reference numeral 1 denotes a main body of a tandem type digital color printer. A platen cover 3 that presses a document 2 onto a platen glass 5 is disposed at an upper portion on one end side of the digital color printer main body 1. An image reading device 4 that reads an image of the document 2 placed on the glass 5 is provided. The image reading device 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 from a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. The image reading element 11 composed of a CCD or the like is scanned and exposed through a reduction optical system, and the color material reflected light image of the document 2 is formed at a predetermined dot density (for example, 16 dots / mm) by the image reading element 11. It is configured to read.
[0051]
The color material reflected light image of the document 2 read by the image reading device 4 is subjected to image processing as, for example, document reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). The image processing apparatus 12 sends a shading correction, a position shift correction, a lightness / color space conversion, a gamma correction, a frame erasing, a color / movement to the reflectance data of the document 2 in the image processing apparatus 12 (Image Processing System). Predetermined image processing such as editing is performed.
[0052]
The image data that has been subjected to the predetermined image processing by the image processing apparatus 12 as described above is an original of four colors of yellow (Y), magenta (M), cyan (C), and black (K) (8 bits each). Converted into color material gradation data (raster data), as described below, image forming units 13K, 13Y, 13M for black (K), yellow (Y), magenta (M), and cyan (C) 13C ROSs 14K, 14Y, 14M, and 14C (Raster Output Scanners). In these ROSs 14K, 14Y, 14M, and 14C, image exposure with laser light is performed according to image data of a predetermined color.
[0053]
Incidentally, inside the tandem type digital color printer main body 1, as described above, four image forming units 13K, 13Y, black (K), yellow (Y), magenta (M), and cyan (C) are provided. 13M and 13C are arranged in parallel at regular intervals in the horizontal direction.
[0054]
These four image forming units 13K, 13Y, 13M, and 13C are all configured in the same manner except that the colors of the images to be formed are different. In general, the images are rotated at a predetermined rotational speed along the arrow direction. A photosensitive drum 15 as a carrier, a scorotron 16 for primary charging as a charging means for uniformly charging the surface of the photosensitive drum 15, and an image corresponding to each color are exposed on the surface of the photosensitive drum 15. ROS 14 as an image exposure device for forming an electrostatic latent image, a developing unit 17 for developing the electrostatic latent image formed on the photosensitive drum 15, and a cleaning device 18.
[0055]
As shown in FIG. 3, the ROS 14 modulates the semiconductor laser 19 according to the image data of each color, and emits a laser beam LB from the semiconductor laser 19 according to the image data. The laser beam LB emitted from the semiconductor laser 19 is deflected and scanned by the rotary polygon mirror 22 via the reflection mirrors 20 and 21, and again the photosensitive drum 15 via the reflection mirror 21 and the plurality of reflection mirrors 23 and 24. Scan exposure is performed on the top.
[0056]
From the image processing apparatus 12, each color is supplied to ROS 14K, 14Y, 14M, and 14C of black (K), yellow (Y), magenta (M), and cyan (C) image forming units 13K, 13Y, 13M, and 13C. Image data (raster data) are sequentially output, and laser beams LB emitted according to the image data from these ROSs 14K, 14Y, 14M, and 14C are the surfaces of the respective photosensitive drums 15K, 15Y, 15M, and 15C. And an electrostatic latent image is formed by scanning exposure. The electrostatic latent images formed on the photosensitive drums 15K, 15Y, 15M, and 15C are black (K), yellow (Y), magenta (M), and magenta by developing units 17K, 17Y, 17M, and 17C, respectively. The toner image is developed as a cyan (C) color toner image.
[0057]
Black (K), yellow (Y), magenta (M), and cyan (C) are sequentially formed on the photosensitive drums 15K, 15Y, 15M, and 15C of the image forming units 13K, 13Y, 13M, and 13C. The toner images of each color are transferred in multiple by the primary transfer rolls 26K, 26Y, 26M, and 26C onto the intermediate transfer belt 25 as an intermediate transfer member disposed below each of the image forming units 13K, 13Y, 13M, and 13C. Is done. The intermediate transfer belt 25 is wound around the drive roll 27, the idle roll 28, the steering roll 29, the idle roll 30, the backup roll 31, and the idle roll 32 with a constant tension. A drive roll 27 that is rotationally driven by a dedicated drive motor with excellent constant speed (not shown) is circulated at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 25, for example, a flexible synthetic resin film such as polyimide is formed in a strip shape, and both ends of the synthetic resin film formed in a strip shape are connected by means such as welding, thereby being endless. A belt-shaped one is used.
[0058]
The black (K), yellow (Y), magenta (M), and cyan (C) toner images transferred onto the intermediate transfer belt 25 in a multiple manner are transferred to the backup roll 31 by the secondary transfer roll 33. The recording paper 34 that has been secondarily transferred onto the recording paper 34 by the pressure contact force and electrostatic force, and onto which the toner images of the respective colors have been transferred, is conveyed to the fixing device 37 by the two conveying belts 35 and 36. The recording paper 34 onto which the toner images of the respective colors have been transferred is subjected to a fixing process with heat and pressure by a fixing device 37 and is discharged onto a discharge tray 38 provided outside the printer body 1.
[0059]
As shown in FIG. 3, the recording paper 34 has a predetermined size from any of a plurality of paper feed trays 39, 40, 41, and a pair of paper feed rollers 42 and a pair of paper transport rollers 43, 44. , 45 are temporarily transported to the registration roll 47 one by one via a paper transport path 46. The recording paper 34 supplied from any one of the paper feed trays 39, 40, 41 is sent onto the intermediate transfer belt 25 by a registration roll 47 that is rotationally driven at a predetermined timing.
[0060]
Then, in the four image forming units 13K, 13Y, 13M, and 13C of black, yellow, magenta, and cyan, as described above, the black, yellow, magenta, and cyan toner images are respectively predetermined. It is formed sequentially at the timing.
[0061]
The photosensitive drums 15K, 15Y, 15M, and 15C, after the toner image transfer process is completed, the residual toner and paper dust are removed by the cleaning devices 18K, 18Y, 18M, and 18C, and the next image formation is performed. Prepare for the process. Further, the residual toner is removed from the intermediate transfer belt 25 with a cleaning blade or a brush by a belt cleaning device 48.
[0062]
By the way, in the tandem type digital color printer configured as described above, the photosensitive drum of each image forming unit is caused by various factors such as vibration during transportation and installation, or temperature change in the machine, as shown below. As a result, positional variations occur in the image, and image misregistration (registration misalignment) occurs.
[0063]
First, in each of the image forming units 13K, 13Y, 13M, and 13C, if the photosensitive drums 15K, 15Y, 15M, and 15C are misaligned, as shown in FIG. 4, the ROSs 14K, 14Y, 14M, and 14C and the photosensitive drums are used. The distances (optical path lengths) between 15K, 15Y, 15M, and 15C fluctuate, and a deviation in magnification in the main scanning direction (laser beam scanning direction) and a deviation in left and right magnifications in the main scanning direction occur. Further, in each of the image forming units 13K, 13Y, 13M, and 13C, when there is a positional deviation along the main scanning direction between the ROS 14K, 14Y, 14M, and 14C and the photosensitive drums 15K, 15Y, 15M, and 15C, FIG. As shown, a margin shift in the main scanning direction occurs.
[0064]
Further, in each of the image forming units 13K, 13Y, 13M, and 13C, as shown in FIG. 6, if the rotation axes of the photosensitive drums 15K, 15Y, 15M, and 15C are inclined, skew deviation occurs. Further, as shown in FIG. 7, when the photosensitive drums 15K, 15Y, 15M, and 15C are misaligned along the sub-scanning direction, a margin shift in the sub-scanning direction occurs.
[0065]
Further, in addition to the above-described registration deviation, in each of the image forming units 13K, 13Y, 13M, and 13C, as shown in FIG. 8, the photosensitive drums 15K, 15Y, 15M, and 15C and the intermediate transfer belt 25 vary in speed. If this occurs, periodic fluctuations (AC fluctuations) in the sub-scanning direction occur, and this causes color registration deviation (hereinafter referred to as “color registration deviation”) between different colors. Further, if the intermediate transfer belt 25 meanders in the main scanning direction, as shown in FIG. 9, periodic fluctuations (AC fluctuations) in the main scanning direction occur, and this causes color registration misalignment between different colors. Will occur.
[0066]
As described above, due to various factors, the magnification deviation in the main scanning direction, the deviation between the left and right magnifications in the main scanning direction, the skew deviation, the sub scanning margin deviation, the main scanning margin deviation, the sub scanning periodic deviation, and the main scanning periodic deviation. However, as shown in FIG. 10, a DC shift (uniform shift) and an AC shift (periodic shift) occur, and color registration shift occurs. It appears.
[0067]
Therefore, in this embodiment, as shown in FIG. 11, a color registration error detection pattern 50 is formed on the intermediate transfer belt 25 at a predetermined timing, and the color registration error detection pattern 50 is detected by the detection means 60. And a registration error correction operation that corrects the color registration error of each of the image forming units 13K, 13Y, 13M, and 13C is executed, and then a color image is formed. The detection means 60 is disposed at both ends of the intermediate transfer belt 25 along the width direction of the intermediate transfer belt 25, for example, and if necessary, both ends and the center along the width direction of the intermediate transfer belt 25. A plurality of (three or more) may be provided at equal intervals along the width direction of the intermediate transfer belt 25, or may be appropriately arranged according to the type of color registration deviation to be detected.
[0068]
As shown in FIGS. 12 and 13, the color registration misalignment detection pattern 50 includes a first chevron mark 51KK composed of the first reference color and a second chevron mark composed of the second measured color. A pattern in which all the colors to be measured are combined with 51YY and the third chevron mark 51KY mark composed of the first color and the second color as one unit is used. The combination of the patterns 50 shown in FIG. 12 is one block for the reference color and the target color. When this pattern is actually used, as shown in FIG. 13, it is repeatedly formed and sampled for several blocks. Here, Embodiment 1 of the present invention will be described on the assumption that sampling for one round of the intermediate transfer belt 25 is performed. A signal for outputting the color registration error detection pattern 50 is stored in advance in, for example, a ROM of a printer output control unit 85 as a registration error correction operation executing unit of the image processing apparatus 12 described later. Of course, the color registration misalignment detection pattern 50 may have another shape.
[0069]
FIG. 14 is a perspective configuration diagram showing the pattern detector 60 for detecting the color registration misalignment.
[0070]
In FIG. 14, reference numeral 61 denotes a housing of the pattern detector 60, and 62 a and 62 b denote two light emitting elements that respectively illuminate the color registration misalignment detection pattern 50 formed on the intermediate transfer belt 25. Reference numerals 63b, 64a, and 64b denote two sets of light receiving elements that respectively receive reflected light from different mountain-shaped marks 51 of the color registration misalignment detection pattern 50 formed on the intermediate transfer belt 25. These two sets of light receiving elements 63a, 63b and 64a, 64b are arranged as shown in FIG. As the two light emitting elements 62a and 62b, for example, LEDs that emit light having a specific wavelength or light having a predetermined wavelength distribution are used. These light emitting elements 62a and 62b are arranged on the intermediate transfer belt 25. These one detection positions are arranged so as to illuminate from opposite diagonal directions inclined by a predetermined angle. The two sets of light receiving elements 63a, 63b and 64a, 64b are arranged in such a manner that their center portions are opposed to or in contact with each other and their both end portions are inclined downward by a predetermined angle with respect to the horizontal direction. Elements 63a, 63b and 64a, 64b are provided, and the light receiving elements 63a, 63b and 64a, 64b are set so that the detection timing and detection angle of the reflected light are different from each other, as shown in FIG. .
[0071]
When the pattern detector 60 detects the color registration deviation detection pattern 50 formed on the intermediate transfer belt 25 as shown in FIG. 15, the linear detector 51 detects the color registration deviation detection pattern 50. As shown in FIG. 15 (a), a smooth mountain-shaped waveform is first output from one light receiving element 63b, and after some delay, the other light receiving element 63a also shows in FIG. 15 (b). Thus, a smooth mountain-shaped waveform is output. Then, by amplifying the waveforms output from these two light receiving elements 63b and 63a, the difference is taken or amplified after taking the difference, as shown in FIG. After falling, an output waveform that rises in a large mountain shape is obtained. Therefore, by taking the difference between the waveforms output from the two light receiving elements 63a and 63b, as shown in FIG. 15 (d), it is possible to detect color registration deviation without using a high-precision sensor such as a CCD. It becomes possible to detect the linear mark 51 of the pattern 50 with high resolution and high accuracy.
[0072]
As described above, the registration error of the toner images of the respective colors formed by the black, yellow, magenta, and cyan image forming units 13K, 13Y, 13M, and 13C is detected using the color registration error detection pattern 50. The
[0073]
Then, in the tandem digital color printer according to this embodiment, an image formed by each image forming unit in accordance with the registration error amount of each color toner image detected using the color registration error detection pattern 50. The operation of correcting the position of is performed. The calculation and correction operation of the correction amount for correcting the position of the image formed by each image forming unit in accordance with the positional shift amount of the toner image of each color detected using the color registration shift detection pattern 50 is as follows. For example, this is performed by a printer output adjusting unit 74 described later.
[0074]
First, in order to correct the coarse margin in the main scanning direction, as shown in FIG. 16A, the photosensitive drums 15K, ROS 14K, 14Y, 14M, 14C of the image forming units 13K, 13Y, 13M, 13C When exposing images on 15Y, 15M, and 15C, the image recording start position in the main scanning direction is determined by the rise of the SOS (Start Of Scan) signal, but the image is actually exposed from the rise of the SOS signal. It is possible to correct the image recording start position in the main scanning direction in units of 1 VCLK (pixels) by changing the count number of VCLK that is a clock signal until an LS (Line Sync) signal that is an enable signal is activated. it can.
[0075]
In order to correct the coarse margin in the sub-scanning direction, as shown in FIG. 16A, the photosensitive drums 15K, ROS 14K, 14Y, 14M, 14C of the image forming units 13K, 13Y, 13M, 13C When an image is exposed on 15Y, 15M, and 15C, the image recording start position in the sub-scanning direction is determined by the rising edge of the TR0 signal. PS is an enable signal that actually performs image exposure from the rising edge of the TR0 signal. By changing the count number of SOS that is a clock signal until the (Page Sync) signal is activated, the recording start position of the image in the sub-scanning direction can be corrected in units of 1 LS (pixels).
[0076]
Next, to correct the skew, as shown in FIG. 16B, the last stage mirror 24 in the ROSs 14K, 14Y, 14M, and 14C is tilted to move the photosensitive drums 15K, 15Y, 15M, and 15C. The inclination of the laser beam to be exposed is corrected.
[0077]
Further, in order to correct the magnification along the main scanning direction, as shown in FIG. 16C, when exposing the image along the main scanning direction with ROS 14K, 14Y, 14M, and 14C, the pixel interval is set. By changing the frequency of the VCLK (video clock: main scanning pixel output clock) signal to be determined, the pixel width can be changed, and the magnification along the main scanning direction can be corrected.
[0078]
In order to correct a minute margin along the main scanning direction, as shown in FIG. 17A, the minute margin along the main scanning direction of one pixel or less is changed by changing the phase of the VCLK signal. Can be corrected.
[0079]
On the other hand, in order to correct a minute margin along the sub-scanning direction, the phase of the SOS signal is changed by controlling the rotation of the polygon mirror 22 as shown in FIG. A minute margin along the sub-scanning direction can be corrected.
[0080]
Further, as shown in FIG. 18A, when the distance between the ROS 14K, 14Y, 14M, 14C and the photosensitive drums 15K, 15Y, 15M, 15C is different between the IN side and the OUT side of the apparatus, As shown in FIG. 18B, the magnification balance is corrected by changing the balance correction value and changing the slope of the frequency of the VCLK signal in accordance with the magnification balance deviation.
[0081]
Further, in order to correct an arbitrary magnification (magnification / balance / partial magnification difference) shift, as shown in FIG. 19, the VCLK (video clock: main scanning pixel output clock) signal and the phase of the pulse in the same cycle are used. A plurality of shifted pulses VCLK1 to 8 are set, and VCLK is created by appropriately selecting the plurality of pulses VCLK1 to 8 in accordance with magnification, balance (horizontal magnification difference), or partial magnification deviation. This makes it possible to correct any magnification (magnification / balance / partial magnification difference) deviation.
[0082]
Further, in order to change the pixel position of the image data in the main scanning direction and the sub scanning direction, as shown in FIG. 20, the correction amount of the pixel position calculated from the shift amount is, for example, −5 pixels in the main scanning direction, By changing the data at the (N, M) data address to the (N-5, M + 4) data address when it corresponds to the scanning direction +4 pixels, the image writing clock is not changed, and only the processing of the image data is performed. Thus, it is possible to correct a deviation in the main scanning direction and the sub-scanning direction.
[0083]
When the LED exposure bar is used instead of ROS as the image exposure apparatus, the pixel output timing in the sub-scanning direction can be controlled by changing the light emission timing. is there.
[0084]
By the way, in this embodiment, a plurality of image forming units that form images of different colors are provided, and images of different colors formed by the plurality of image forming units are recorded directly or via an intermediate transfer member. In a color image forming apparatus for forming a color image by transferring onto a medium, a temperature detecting means for detecting a temperature in the color image forming apparatus main body, and a temperature in the apparatus main body detected by the temperature detecting means. Based on this, the image forming apparatus is configured to include a prediction correction unit that predicts and corrects the color registration misalignment amount in the plurality of image forming units.
[0085]
Further, in this embodiment, the prediction correction unit predicts and corrects the color registration deviation amount at a changing temperature interval according to the detected value of the temperature in the apparatus main body detected by the temperature detection unit. The correction operation is performed.
[0086]
Furthermore, in this embodiment, at least one prediction correction table that predicts and corrects the color registration deviation amount according to the detected value of each temperature in the apparatus main body detected by the temperature detecting means is provided. Has been.
[0087]
Furthermore, in this embodiment, every time the color registration deviation amount prediction correction operation is executed, the upper limit value and the lower limit value of the temperature interval at which the next color registration deviation amount prediction correction operation is executed are determined. Has been.
[0088]
FIG. 2 is a block diagram showing a control circuit of a tandem type digital color printer as a color image forming apparatus according to Embodiment 1 of the present invention.
[0089]
In FIG. 2, reference numeral 71 denotes an IOT main controller that also functions as a registration error correction operation execution means and a prediction correction means for controlling an image forming operation in the image output apparatus 100 of the digital color printer, and 72 is an input via an interface 73. ESS to which image data is input from the image reading device 4 or a personal computer (not shown), 74 is a RAM provided in the ESS 73, and 75 is a temperature detection means for detecting the temperature inside the printer main body 1. A sensor 76 and a RAM provided in the image processing apparatus 12, and a pattern detector 60 for detecting a color registration misalignment detection pattern 50 formed on the intermediate transfer belt 25 are shown. The temperature sensor 75 is disposed, for example, at the center of the printer main body 1.
[0090]
In the above configuration, in the tandem type digital color printer according to the first embodiment, the registration control operation for correcting the color registration shift caused by the temperature rise in the apparatus main body is efficiently performed as follows. By making it possible, the state in which image forming operation is impossible is reduced, so-called downtime is reduced, the toner consumption for forming a registration patch is reduced, the load on the cleaning member is reduced, and the waste toner collection capacity is further reduced. Can be reduced.
[0091]
That is, in the tandem type digital color printer according to the first embodiment, when the temperature (absolute temperature) in the printer main body 1 changes such as rising or falling, as shown in FIG. Fluctuates. Here, as the color registration deviation amount, for example, the maximum registration deviation amount of the main scanning magnification deviation is used, but is not limited to this, and as described above, other sub-registration deviation amount: lead Of course, other deviation amounts such as skew deviation, BOW deviation, main scanning registration deviation amount: side registration deviation, left-right magnification deviation, partial magnification deviation, and the like may be used.
[0092]
The color registration temperature characteristic curve showing the variation of the color registration deviation amount with respect to the temperature (absolute temperature) in the printer body 1 has a certain relationship with the absolute temperature in the printer body 1 as shown in FIG. Therefore, by storing the color registration temperature characteristic curve information in a memory in the printer main body 1 in advance, the color registration deviation amount can be predicted and corrected.
[0093]
Here, as shown in FIG. 22, the color registration temperature characteristic curve information corresponds to the absolute temperature in the printer main body 1 and the temperature intervals Δt 1, Δt 2, Δt 3 at which a constant color registration deviation amount Δerror occurs. , Δt4.
[0094]
In this embodiment, the color registration error detection pattern formed by each image forming unit is transferred onto the same pattern detection member at a predetermined timing together with the prediction correction of the color registration error. A color registration error detection pattern transferred onto the pattern detection member is detected and a color registration error correction operation is executed.
[0095]
Assuming that the state when the color registration misalignment correction operation is completed is A in FIG. 22, the absolute temperature T in the printer main body 1 at this time is stored as T0 with this state A as a reference. When the temperature T0 can be grasped, absolute temperature conditions T1, T2, T3, and T4 that generate a specified color registration deviation change amount Δerror after the temperature rise from the temperature T0 are calculated.
[0096]
These absolute temperature conditions T1, T2, T3, and T4 are temperatures at which color registration deviation prediction correction is performed. The temperature T1 has a color registration deviation of “+ Δerror” with respect to the reference, and similarly the temperature T2 has a reference to “reference”. A color registration shift of + 2Δerror ”means a temperature at which a color registration shift of“ −Δerror ”occurs at temperature T4.
[0097]
Then, every time the temperature T in the printer main body 1 detected by the temperature sensor 75 reaches T1, T2, T3, T4, a prediction correction based on the color registration misalignment temperature is performed. At this time, a correction operation for correcting the color registration deviation amount predicted from the temperatures T1, T2, T3, and T4 is executed. For example, since the color registration is deviated by Δerror at the temperature T1, the color registration deviation amount is corrected by “−Δerror”. Similarly, at the temperature T2, the color registration is deviated by + 2Δerror from the reference. Therefore, the color registration misregistration amount is corrected by “−2Δerror”. Similarly, at the temperature T4, the color registration misregistration amount is corrected by −Δerror with respect to the reference, so the color registration misregistration amount is corrected by “+ 2Δerror”. That's fine. The same applies to the temperature T3. Here, four temperature conditions of T1, T2, T3, and T4 are set, but finer temperature increments may be used.
[0098]
More specifically, in the first embodiment, as shown in FIG. 21, the IOT main controller 71 first executes a color registration misalignment correction operation (step 101), and then the printer main body 1 by the temperature sensor 75. Is detected and confirmed (step 102), the detected temperature T in the printer main body 1 is set as the reference temperature T0 (step 103), and the condition temperatures T1, T2 for executing the color registration shift prediction correction , T3, T4 are calculated.
[0099]
FIG. 22B shows an example of a temperature parameter table for calculating condition temperatures T1, T2, T3, and T4 for executing color registration misalignment prediction correction. Here, the usable temperature of the digital color printer is set to 10 ° C. or higher and lower than 45 ° C., but it may of course be set to be usable in a temperature range other than this. In FIG. 22B, the absolute temperature represents the detected value itself of the temperature in the printer main body 1 detected by the temperature sensor 75, and the absolute temperature value in this table is equal to or higher than the temperature. The temperature range below the temperature is shown. For example, in FIG. 22B, the absolute temperature of 10 (° C.) means a temperature range of 10 ° C. or more and less than 15 ° C. Here, the absolute temperature is not shown as a physical absolute temperature, but an absolute temperature relative to a relative temperature (temperature difference between a certain temperature and a certain temperature) This is because 10 ° C. means a temperature of 10 ° C. and 20 ° C. means a temperature of 20 ° C.
[0100]
As shown in FIG. 22 (a), this table shows, for example, a deviation in read registration when the absolute temperature in the printer main body 1 is changed by, for example, a temperature Δt1 (= TB−TA) from the temperature TA to the temperature TB. The amount of change in temperature when changing by a certain amount Δerror is used as a parameter. Here, the lead registration error amount will be described as an example of the color registration error amount on the vertical axis. However, the present invention is not limited to this, and as described above, other sub-scan registration error amounts: skew error, BOW error. In addition, a table of each element to be corrected is required among the main-scanning registration deviation amount: side registration deviation, magnification deviation, left-right magnification deviation, partial magnification deviation, and the like. Each element to be corrected may be all of the color registration misalignment or a part of them. Further, a table may be provided for each correction target element, and a common table may be used for those that can be shared (those with the same absolute temperature change amount per unit deviation).
[0101]
Further, here, the temperature change amount when the maximum registration deviation amount changes by a certain amount Δerror is used as a parameter when the in-machine temperature changes by the temperature change amount, for example, the maximum registration deviation of the main scanning magnification deviation. This is because the registration error may occur by the amount of deviation (allowable value). Therefore, if the registration error correction operation is executed at this timing, the number of registration error correction operations can be reduced as much as possible.
[0102]
When the temperature at the first registration misalignment correction operation is 28.0 ° C. in absolute temperature, the condition temperature at the next registration control operation is as shown in FIG. It becomes the value Tl.
Topper = 28.0 + 2.5 = 30.5 ° C.
Tlower = 28.0−2.5 = 25.5 ° C.
[0103]
Here, 2.5 ° C. in the equation for calculating the upper limit value Tu and the lower limit value Tl is 2.5, which is the upper parameter (upper) of the row of 25 ° C. or more and less than 30 ° C. in the table shown in FIG. It is a value of 2.5 ° C. as the lower limit parameter.
[0104]
As described above, the IOT main controller 71 performs the registration deviation correction operation (registration operation), and then, based on the current temperature T, the upper limit that is the condition temperature during the next registration deviation correction operation, as shown in FIG. The value Tu and the lower limit value Tl are determined (step 103), and it is determined whether or not the temperature prediction correction timing is reached (step 104).
[0105]
Here, the temperature prediction correction timing is as follows: when the device is turned on, when a print job starts, at the top of each page in the job, when each page in the job ends, when the print job ends, when the sleep mode is entered, when the sleep mode is restored Or when the copy / print configuration is changed.
[0106]
The copy / print configuration change means changes such as image size change, resolution change, image resolution, or process speed change corresponding to paper (thick paper, plain paper, OHP).
[0107]
If it is not the temperature prediction correction timing, the IOT main controller 71 stands by until the temperature prediction correction timing is reached (step 104). The temperature T is detected and confirmed (step 105), and it is determined whether the in-machine temperature T is equal to or higher than the upper limit value Tn determined during the previous regicon operation or lower limit value Tn (step 106). If the upper limit value Tn is not equal to or lower than the lower limit value Tn, the process returns to step 104. If the in-flight temperature T is equal to or higher than the upper limit value Tn or equal to or lower than the lower limit value Tn, the prediction correction operation for the temperature Tn is performed. (Step 107).
[0108]
In this way, by performing the color registration misalignment prediction correction operation based on the reference temperature T0, it is possible to correct the color registration misalignment associated with the change in the in-machine temperature T of the printer main body 1.
[0109]
However, in the above digital color printer, in addition to fluctuations in the temperature T in the machine, fluctuations with time of the image forming apparatus (changes with time of drive mechanism components), disturbances (impacts when moving the apparatus, installation floor environment), and image formation are affected. The color registration misalignment state at the reference temperature T0 changes due to factors such as a change in the state of the component to be used (change in the image carrier due to jam clearing) and replacement of the component that affects image formation.
[0110]
If the color registration misalignment amount at the reference temperature T0 changes due to the above various factors, the color registration misalignment prediction correction at the temperatures T1, T2, T3, and T4 also has an error.
[0111]
Therefore, in the first embodiment, in order to prevent this, a registration error correction operation for forming a color registration error detection pattern is performed. The timing for performing this registration error correction operation is as follows: immediately after device assembly, when the device is installed, when the device is turned on, when the device is on standby, after a certain period of time has elapsed, when the print job starts, after the print job is completed, After the elapse of time, after a certain time elapses), when the sleep mode is shifted, when the sleep mode is restored, and the like.
[0112]
Therefore, the IOT main controller 71 determines whether or not it is time to execute the registration deviation correction operation after performing the prediction correction operation for the temperature Tn (step 107). The IOT main controller 71 returns to step 104 when it is not time to execute the registration error correction operation, and returns to step 101 when it is time to execute the registration error correction operation. The operation is to be carried out.
[0113]
In this way, the reference registration error correction operation is performed at a predetermined registration error correction operation execution timing (step 101). Between these registration error correction operations, prediction of color registration error, which is the processing of the present invention, is performed. Execute correction operation.
[0114]
It should be noted that when there is almost no factor that causes a change in the color registration misalignment other than the change in the in-machine temperature T, it is of course possible to execute only the color registration misalignment predictive correction operation.
[0115]
As described above, in this embodiment, by performing the color registration misalignment predictive correction operation, the frequency of performing the color registration misalignment correction operation associated with the formation of the color registration misalignment amount detection pattern is greatly increased compared to the conventional case. State that can be reduced and image forming operation is impossible Reduction of so-called downtime, reduction of toner consumption for forming a registration patch, reduction of load on the cleaning member, waste toner collection capacity, etc. Can be reduced.
[0116]
Further, in the case of the first embodiment of the present invention, if the toner consumption for forming the downtime, the registration patch, or the load on the cleaning member is the same as that of the conventional apparatus, the registration deviation correcting operation is performed. By increasing the number of times, it is possible to further improve the accuracy of the registration error correction operation.
[0117]
Embodiment 2
In the second embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, the color registration deviation amount to be predicted and corrected is set with a constant temperature interval. It is configured to change.
[0118]
That is, in the first embodiment, as shown in FIGS. 22 (a) and 22 (b), the temperature interval data (Δt1, Δt2, Δt3, t4) that changes with respect to a certain allowable deviation amount (correction amount) is used as a condition. Although the temperature is set, as shown in FIG. 23, the temperature interval data is set to a constant Δt, and the allowable deviation amount (correction value) corresponding to the temperature is changed as Δerror1, Δerror2, Δerror3, Δerror4, and Δerror5. You may comprise as follows. In this case, the maximum deviation amount Δerror5 needs to be within an allowable range.
[0119]
FIG. 23B shows an example of a correction parameter table in a case where the temperature change amount is constant and the correction amount corresponding to the absolute temperature value is changed when the color registration misalignment prediction correction is executed. Here, the usable temperature of the digital color printer is set to 10 ° C. or higher and lower than 45 ° C., but it may of course be set to be usable in a temperature range other than this. In FIG. 23 (b), the absolute temperature represents the detected value itself of the temperature in the printer body 1 detected by the temperature sensor 75, and the absolute temperature value in this table is equal to or higher than the temperature. The temperature range below the temperature is shown.
[0120]
The table shown in FIG. 23B corresponds to a color registration error correction parameter corresponding to an absolute temperature value on the assumption that color registration error prediction correction is executed every time the temperature in the printer body 1 changes by 5 ° C. It is set to change.
Here, assuming that the temperature at the first registration deviation correction operation is 24.0 ° C., it is a prediction correction in increments of 5 ° C. Therefore, the temperature condition of the next prediction correction is
Topper = 24.0 + 5.0 = 29.0 ° C.
Tlower = 24.0-5.0 = 19.0 ° C.
It becomes. When the in-machine temperature rises and reaches 29.0 ° C., correction for the lead registration correction amount “3” derived from the table of FIG. 23B is executed.
[0121]
Similarly, when the temperature falls from 29.0 ° C. by 5 ° C. to 24.0 ° C., the correction for the read registration correction amount “−4” derived from the table of FIG. 23B is executed. To do.
[0122]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0123]
The basic prediction correction process, the temperature prediction correction execution timing, and the registration deviation correction operation execution timing as the reference have been described above.
[0124]
The frequency of the registration misalignment correction operation that requires the formation of the color registration misalignment detection pattern is preferably as small as possible. Instead, it is desirable to increase the frequency of the temperature prediction correction.
[0125]
For example, a registration error correction operation that requires formation of a color registration error detection pattern is performed only immediately after the assembly of the color image forming apparatus, and after that, all color registration errors can be corrected by temperature prediction correction. Is possible.
[0126]
In that case, the color image forming apparatus may be turned off or may enter a sleep mode. In this case, it is necessary to hold data of absolute temperature conditions T1, T2, T3, and T4. In this case, the data may be held in a non-volatile memory or a storage medium that can maintain information in an energization cut-off state instead. As a result, it is possible to perform prediction correction based on the temperature condition determined during the previous registration error correction operation without executing the registration error correction operation immediately after the apparatus is turned on.
[0127]
In addition, the registration error correction operation that is performed after the power is turned on or when returning from the sleep mode, in which the FCOT and the FPOT (the time from the copy / print instruction to the output of the first copy / print) are regarded as important, By performing prediction correction based on absolute temperature, color registration misalignment is corrected to some extent, and as soon as the first print job is completed (job end), a registration misalignment correction operation for forming a color registration misalignment detection pattern may be executed. It is valid.
[0128]
Further, although related to FCOT and FPOT, the registration error correction operation for forming a color registration error detection pattern cannot be executed due to a limitation during warm-up of the fixing device. It is effective to perform prediction correction based on the absolute temperature.
[0129]
Embodiment 3
24 and 25 show the third embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment. In the third embodiment, the temperature detecting means is shown in FIG. According to the detected value of each temperature in the apparatus main body detected by the above, at least one prediction correction arithmetic expression for predicting and correcting the color registration deviation amount is provided.
[0130]
That is, in the first embodiment, as shown in FIG. 22A, the color registration characteristic indicating how the color registration deviation amount changes with respect to the temperature (absolute temperature) in the printer body 1. A prediction correction table that predicts and corrects color registration misalignment corresponding to the detected value of each temperature in the printer main body 1 detected by the temperature sensor based on the color registration characteristic curve is obtained. Was.
[0131]
However, instead of the prediction correction table, it is possible to provide at least one prediction correction arithmetic expression for predicting and correcting the color registration misalignment amount.
[0132]
Therefore, in the case of the third embodiment, a color registration characteristic curve as shown by a broken line in FIG. 24 is represented by a plurality of straight lines f (t), g (t), h (t) (or at least one secondary (Approximate curve) is stored in RAM, NVRAM, etc., and from these approximation formulas (calculation formulas) f (t), g (t), h (t), it corresponds to a specific deviation amount Δerror. The temperature upper and lower limits are calculated, and the predicted correction amount when the temperature is reached is calculated every time.
[0133]
For example, when the temperature during the registration error correction operation (registon operation) is T0, the absolute temperature T0 is in the range of the arithmetic function f (t). Note that the temperature range to which the function f (t), which is each arithmetic expression, is applied is predetermined as shown in FIG. Here, the function f (t) can be expressed as follows. A and a indicate the slope and intercept of the function f (t) representing the approximate straight line.
f (t) = At + a (1)
[0134]
Assuming that the allowable temperature range to be obtained is Δt and the constant maximum registration deviation amount is Δerror =, from the equation (1),
Δerror = AΔt + a (2)
Δt = (1 / A) (Δerror−a) (3)
It becomes.
[0135]
Therefore, the temperature upper limit value Upper and the lower limit value Tlower that determine the start condition for the next prediction correction are:
Toper = T0 + Δt = T0 + (1 / A) (Δerror−a) (4)
Tlower = T0−Δt = T0− (1 / A) (Δerror−a) (5)
And it is sufficient.
[0136]
As the arithmetic expressions stored in the RAM, NVRAM, etc., each approximate expression is shown.
f (t) = At + a (1)
g (t) = Bt + b (1) ′
h (t) = Ct + c (1) "
F (t), g (t), and h (t) may be stored as they are, or parameters A / a, B / b, and C / c representing approximate expressions may be stored as information. good.
[0137]
Further, (1 / A) (Δerror-a), (1 / B) (Δerror-b), and (1 / C) (Δerror-c) may be stored as information. The effective temperature ranges of the approximate expressions f (t), g (t), and h (t) are also provided as information.
[0138]
On the other hand, when the temperature range spans a plurality of functions, the temperature may be calculated by the adjacent function for the error value that is out of the function, or the condition is bad, that is, the deviation change amount per temperature is large (this There is no problem even if the temperature condition is calculated with the function of the larger case).
[0139]
In this case, for example, as shown in FIG. 25, the in-machine temperature when the registration operation (or registration deviation prediction correction) is performed is T0, and the temperature T0 is Tb (approximate equations f (t) and g (t ), When Tu and Tl are calculated once by the function of f (t), the temperature is calculated by the function of g (t) by the amount of deviation Δerror2 over which Tu exceeds Tb. The upper limit value Tu ′ may be obtained by calculation.
[0140]
However, there is no problem because the allowable deviation amount is not exceeded even if a function having a large slope, in this case, Tu calculated by f (t) is directly used as the upper limit value. In this case, the arithmetic processing is reduced, but the number of registration correction prediction correction operations increases.
[0141]
In the third embodiment, the case where the calculation process is executed every time based on the approximate expression of the color registration characteristic curve has been described. However, the in-machine temperature T0 during the initial registration control operation is set to a known constant value in advance. In the case where it is possible, based on the in-machine temperature T0 at the time of the initial registration control operation, each temperature value obtained by the approximate expression (1) or the like may be obtained in advance by calculation and stored in the storage means. . However, in consideration of the case where the in-machine temperature T0 during the initial registration control operation is different in a state where the printer is actually used, the printer has at least one temperature interval calculation formula that determines the temperature interval as a fixed value. At the time of detection, a temperature interval for determining whether to start the registration deviation correction operation may be calculated based on the calculation formula, and these temperature intervals may be stored as fixed values.
[0142]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0143]
Embodiment 4
FIG. 26 shows a tandem full-color printer as an image forming apparatus according to Embodiment 4 of the present invention.
[0144]
In FIG. 26, reference numeral 200 denotes a main body of a tandem type full-color printer. Inside the printer main body 200, each of yellow (Y), magenta (M), cyan (C), and black (K) is provided. Image forming units 201, 202, 203, and 204 having photosensitive drums (image carriers) 211, 212, 213, and 214, and a charging roll for primary charging that contacts these photosensitive drums 211, 212, 213, and 214 ( Contact type charging devices) 221, 222, 223, 224 and image books for irradiating yellow (Y), magenta (M), cyan (C), and black (K) laser beams 231, 232, 233, 234 And electrostatic latent images formed on the photosensitive drums 211, 212, 213, and 214 are yellow (Y), magenta (M), cyan (C), The developing devices 24, 242, 243, and 244 that develop with black (K) color toner and the two photosensitive drums 211 and 212 out of the four photosensitive drums 211, 212, 213, and 214 contact each other. A first primary intermediate transfer drum (intermediate transfer member) 251 and a second primary intermediate transfer drum (intermediate transfer member) 252 that contacts the other two photosensitive drums 213 and 214, and the first and second primary transfer members. A secondary intermediate transfer drum (intermediate transfer member) 253 that contacts the intermediate transfer drums 251 and 252 and a final transfer roll (transfer member) 260 that contacts the secondary intermediate transfer drum 253 constitute the main part. Yes.
[0145]
The photoconductor drums 211, 212, 213, and 214 are arranged at regular intervals so as to have a common tangential plane. Further, the first primary intermediate transfer drum 251 and the second primary intermediate transfer drum 252 are surfaces whose rotational axes are parallel to the photosensitive drums 211, 212, 213, and 214 and have predetermined symmetry planes as boundaries. They are arranged in a symmetrical relationship. Further, the secondary intermediate transfer drum 253 is disposed so that the rotation axis thereof is parallel to the photosensitive drums 211, 212, 213, and 214.
[0146]
Laser light 231, 232 corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) is applied to the surface of the photosensitive drums 211, 212, 213, and 214 by an image writing device 230. 233 and 234 are irradiated, and an electrostatic latent image corresponding to input image information for each color is formed. In addition, the electrostatic latent images corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) formed on the surfaces of the photosensitive drums 211, 212, 213, and 214 are as follows. It is developed by corresponding color developing devices 241, 242, 243, and 244, and yellow (Y), magenta (M), cyan (C), and black (K) are formed on the photosensitive drums 211, 212, 213, and 214. It is visualized as a toner image of each color.
[0147]
Next, the yellow (Y), magenta (M), cyan (C), and black (K) toner images formed on the respective photosensitive drums 211, 212, 213, and 214 are the first primary images. The secondary transfer is electrostatically performed on the intermediate transfer drum 251 and the second primary intermediate transfer drum 252. The yellow (Y) and magenta (M) color toner images formed on the photoconductive drums 211 and 212 are cyan (on the first primary intermediate transfer drum 251 and cyan (213) formed on the photoconductive drums 213 and 214, respectively. C) and black (K) toner images are respectively transferred onto the second primary intermediate transfer drum 252. Accordingly, on the first primary intermediate transfer drum 251, the single color image transferred from either the photosensitive drum 211 or 212 and the two-color toner images transferred from both the photosensitive drums 211 and 212 are superimposed. A double color image is formed. In addition, similar single-color images and double-color images are formed on the second primary intermediate transfer drum 252 from the photosensitive drums 213 and 214.
[0148]
The single-color or double-color toner images formed on the first and second primary intermediate transfer drums 251 and 252 in this way are electrostatically and tertiary-transferred onto the secondary intermediate transfer drum 253. Therefore, a final toner image from a single color image to a quadruple color image of yellow (Y), magenta (M), cyan (C), and black (K) is formed on the secondary intermediate transfer drum 253. Will be.
[0149]
Next, the final toner image from the single color image to the quadruple color image formed on the secondary intermediate transfer drum 253 is thirdarily transferred onto the paper P passing through the paper conveyance path by the final transfer roll 260. . The paper P passes through the paper transport path from the paper feed roll 290 and is fed into the nip portion between the secondary intermediate transfer drum 253 and the final transfer roll 260. After this final transfer step, the final toner image formed on the paper is fixed by the fixing device 270, and a series of image forming processes is completed.
[0150]
In this embodiment, on the image density detection medium such as the final transfer roll 260 and the secondary intermediate transfer drum 253, the color registration misalignment detection pattern 320 is shifted to the same position in the axial direction and in the process direction. , 321, the color registration deviation detection patterns 320 and 321 for each color can be detected by one optical density detection means. As the color registration misalignment detection patterns 320 and 321, for example, those shown in FIG. 27 are used.
[0151]
In this embodiment, the color registration misalignment detection patterns 320 and 321 are transferred onto the final transfer roll 260, and the density of the color registration misalignment detection patterns 320 and 321 transferred onto the final transfer roll 260 is determined as follows. The optical density sensor 300 is configured to detect.
[0152]
As shown in FIG. 28, the optical density sensor 300 is arranged at the axial center of the final transfer roll 260 so as to be positioned on the radial extension line on the outer periphery of the final transfer roll 260. The optical density sensor 300 is attached in a fixed state in the holder 301. A cleaning device 800 including a blade-like final cleaning member 801 is disposed below the final transfer roll 260. In FIG. 28, reference numeral 802 denotes a toner collection box, 803 a support frame for the final transfer roll 260, 804 a static eliminator provided on the support frame 803, and 805 a bias plate.
[0153]
In addition, as shown in FIG. 29, the optical density sensor 300 is a specular reflection type sensor that detects specular reflection light, and has a predetermined incident angle φ with respect to the detection position on the surface of the final transfer roll 260. In order to detect the specularly reflected light that is emitted from the light emitting element 302 to the detection position on the surface of the final transfer roll 260 and is specularly reflected from the detection position. The light receiving element 303 is formed of a phototransistor or the like that is disposed at an angle of reflection equal to the predetermined incident angle with respect to the detection position on the surface of the roll 260.
[0154]
Then, the color registration deviation detection patterns 320 and 321 are detected by the optical density sensor 300, and the color registration deviation is corrected at a predetermined timing.
[0155]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0156]
Embodiment 5
FIG. 33 shows a fifth embodiment of the present invention. The same parts as those in the first embodiment will be described with the same reference numerals. In the fifth embodiment, the prediction correction means includes The temperature at which the previous prediction correction operation is executed is used as the reference temperature when the prediction correction operation is executed by the prediction correction means. In FIG. 33, A to F in the upper diagram are temperature states A to F, and A, B1, B2 to F1, and F2 in the lower diagram are states A, B1, B2, F1, and F2 without color registration. To do.
[0157]
In the fifth embodiment, the prediction correction unit calculates the color registration deviation amount predicted and corrected by the prediction correction unit, the relative temperature difference from the temperature during the previous prediction correction operation, and the current prediction correction. The calculation is based on the temperature in the apparatus main body at the time of execution.
[0158]
Further, in the fifth embodiment, the prediction correction unit calculates the color registration deviation amount predicted and corrected by the prediction correction unit, the relative temperature difference from the temperature at the previous execution of the registration deviation correction operation, and the current time. It is configured to calculate based on the temperature in the apparatus main body when the prediction correction is performed.
[0159]
Furthermore, in the fifth embodiment, the prediction correction unit calculates the color registration deviation amount predicted and corrected by the prediction correction unit, the relative temperature difference from the temperature during the previous prediction correction operation, and the previous registration. Of the relative temperature differences from the temperature at the time of the deviation correction operation execution, the smaller relative temperature difference and the temperature in the apparatus main body at the time of the current prediction correction execution are calculated.
[0160]
That is, in the fifth embodiment, the IOT main controller 71 as a prediction correction unit executes a prediction correction operation for predicting and correcting the color registration deviation amount. The IOT main controller 71 executes the prediction correction operation. Instead of using the temperature in the apparatus main body when the registration error correction operation is executed by the registration error correction operation executing means, the temperature at which the previous prediction correction operation was executed is used as the reference temperature at the time It is configured as follows.
[0161]
More specifically, in the fifth embodiment, the color misregistration correction leads to the occurrence of downtime in which the color image forming apparatus cannot execute the color image forming operation and the increase in wasteful consumption of toner. The number of operations is reduced, and the color registration misalignment amount is suppressed as much as possible only by performing prediction correction based on temperature.
[0162]
FIG. 33 shows a case in which the prediction correction operation based on the temperature when the machine operation (power-on or print job, etc.) and non-operation (power-off, low power mode, etc.) are repeated after the registration error correction operation is executed. This shows how the temperature in the machine changes and the color registration shift changes.
[0163]
In FIG. 33, when the registration error correction operation associated with the formation and detection of the color registration error detection pattern is executed and the temperature (absolute temperature) in the apparatus is A, the registration error correction operation is performed. It is assumed that the color registration error is a reference deviation state (ideally a state where the color registration deviation is zero) in the executed absolute temperature state A.
[0164]
At this time, the IOT main controller 71 uses T1 and T3 as the condition temperatures when the next prediction correction is started in the same manner as in the above embodiment, based on the in-machine temperature T0 when the absolute temperature state is A. Set. These set temperatures of T1 and T3 are temperatures defined in consideration of an allowable amount of color registration deviation.
[0165]
Next, when a color image is formed in the color image forming apparatus and the internal temperature reaches the set temperature T1 (temperature state B), as shown in FIG. 33, the IOT main controller 71 performs the first time. A prediction correction operation is executed (prediction correction operation 1). At this time, the color registration error is reduced from the color registration error state B1 to the color registration error state B2 by executing the prediction correction operation. The IOT main controller 71 sets, for example, T2 and T0 as condition temperatures for starting the next prediction correction when the prediction correction operation 1 is executed. Here, the IOT main controller 71, based on the temperature T0 when the previous registration deviation correction was executed and the current in-machine temperature (absolute temperature) T1, are the temperature conditions T2 and T0 that are the starting temperature for the next prediction correction. Set.
[0166]
When the in-machine temperature of the color image forming apparatus further rises and the in-machine temperature reaches T2 and reaches the temperature state C, a second prediction correction operation is executed by the IOT main controller 71 (prediction correction operation 2). The registration error is reduced from the color registration error state C1 to the color registration error state C2.
[0167]
Next, predictive correction based on temperature when the color image forming apparatus is in an operating state after a long non-operating state is considered.
[0168]
Here, as described above, the non-operating state refers to a state in which there is no cause for an increase in the internal temperature as in the power-off or stop power mode, and the internal temperature decreases (a state in which the ambient temperature outside the device approaches). The operating state means a state in which the temperature inside the apparatus rises like a power-on or a print job.
[0169]
The lower limit value of the start condition temperature of the next prediction correction operation set after executing the prediction correction operation 2 as described above is, for example, T1, but in the non-operating state, generally, the control device is not energized. Is not executed, the prediction correction operation is executed immediately after the operation state is entered. However, the prediction correction may be executed even in the non-operating state as long as the prediction correction can be executed even when the control device is in the energized state even in the non-operating state.
[0170]
Assuming that the in-machine temperature immediately after the operation state for executing the prediction correction is T3, the color registration shift is based on the relative temperature difference from the temperature T2 to T3 in the previous prediction correction operation and the in-machine temperature T3. Predict the amount and correct the amount.
[0171]
However, as described above, in the prediction correction based on the temperature, the correction amount is calculated by storing the characteristics of the absolute temperature versus color registration deviation as shown in FIG. 22A as a table or an arithmetic expression in advance. . These prediction correction amounts are approximate values (or approximate expressions) to the last, and are values or arithmetic expressions that do not take into account variations in device differences between machines. Therefore, as shown in FIG. 33, the prediction correction inevitably causes an error as compared with the registration error correction operation (feedback) associated with the formation and detection of the color registration error detection pattern.
[0172]
This error is caused by repeating the prediction correction operation a plurality of times without executing the registration error correction operation associated with the formation and detection of the color registration error detection pattern, or if the error due to relative temperature change is large. growing. Specifically, the difference between the color registration misalignment state A in which the registration misalignment correction operation in FIG. 33 is executed and the color registration misalignment state C2 in which the prediction correction operation is executed becomes an error due to the prediction correction operation.
[0173]
Therefore, in order to reset the error of the accumulated prediction correction operation, in the vicinity of the temperature at the registration deviation correction operation, the temperature at the registration deviation correction operation is used as a reference instead of the temperature at the previous prediction correction. It is better to carry out predictive correction based on the relative temperature difference from the temperature at the registration misalignment correction operation and the temperature in the apparatus main body at the time of the current predictive correction execution to calculate the color registration misalignment amount.
[0174]
In the fifth embodiment, in the prediction correction in the color registration state D1, the color registration deviation amount that occurs when the in-machine temperature changes from T0 to T3 is predicted, and the correction value (set value) after the registration deviation correction operation is calculated. Make corrections in the form of updates. That is, when the prediction correction operation is repeated a plurality of times, the temperature at which the next prediction correction operation is executed may be determined based on the temperature at the previous prediction correction operation, but the non-operation state continues for a long time. When the temperature inside the device changes greatly, such as when the temperature of the device is changed, the relative temperature difference between the temperature at the previous prediction correction operation and the current prediction correction operation, the temperature at the previous registration deviation correction operation, and the current The relative temperature difference with the prediction correction operation is compared, and the one with the smaller temperature difference is selected. Then, when the relative temperature difference between the previous registration deviation correction operation and the current prediction correction operation is smaller, the temperature at the next prediction correction is determined based on the temperature difference.
[0175]
The color registration correction value (set value) immediately before the prediction correction operation 3 is a value updated (set) in the previous prediction correction operation 2, and after the registration deviation correction operation required in the prediction correction operation 3. The correction value (setting value) must be stored in a non-volatile memory such as NVM. Here, the correction value (setting value) after the registration error correction operation is used to grasp the color registration error state at the time of registration error correction. However, depending on the correction function processing method, the previous or previous registration error correction operation The color registration misalignment amount may be stored and added to the color registration misalignment amount predicted during the predictive correction operation to newly calculate a correction value (set value). That is, when the prediction correction operation is executed, the color registration misalignment amount at the previous or previous registration misalignment correction operation is taken into consideration and added to the color registration misalignment amount predicted at the current prediction correction operation, You may comprise so that a correction value (setting value) may be calculated anew by calculating.
[0176]
Next, the predicted temperature correction operation 4 is executed even when the in-machine temperature reaches the start condition temperature T4 of the next prediction correction operation set after the prediction correction operation 3. The in-machine temperature T4 at this time is closer to the temperature T0 during the registration error correction operation than the temperature T3 during the previous prediction correction operation 2. At this time, as described in the process of the predicted temperature correction operation 3, the temperature T0 at the registration error correction operation, which is a close value, is used instead of the temperature T3 at the previous prediction correction operation. It is better to predict and correct the color registration shift amount due to the temperature change from T0 to T4 on the basis of the time of operation, and this can reduce the error due to the prediction correction.
[0177]
Note that the prediction correction operation 5 shown in FIG. 33 moves away from the temperature T0 during the registration deviation correction operation, and therefore, correction similar to the prediction correction operations 1 and 2 as described above may be performed.
[0178]
As another method, in calculating a correction value (set value) at the time of predictive correction, the reference may always be the temperature at the registration misalignment correction operation. At this time, the start condition of the predictive correction operation is specified immediately after the registration misalignment correction operation from the temperature specified from the temperature at the registration misalignment operation, and after the predictive correction operation is executed, from the predictive correction operation temperature. The temperature may be used, or the reference condition in the start condition may always be the temperature at the time of registration deviation correction, and the start condition temperature for prediction correction may be defined in multiple stages. For example, the start condition temperature of the predictive correction operation is defined in multiple stages as (T0-7) ° C./(T0-4)° C./(T0+5)° C./(T0+11)° C. In the case where the temperature rises, (T0 + 5) The first prediction correction operation may be executed at ° C, and when the temperature further increases (T0 + 11) ° C, the second prediction correction operation may be executed.
[0179]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0180]
Embodiment 6
In the sixth embodiment, the prediction correction unit is configured to execute prediction correction every time an image is formed on a recording medium.
[0181]
In the sixth embodiment, the prediction correction unit predicts the color registration deviation amount every time an image is formed on the recording medium, and the predicted value of the color registration deviation amount exceeds a predetermined deviation amount. Alternatively, the prediction correction may be executed only on the basis of the above.
[0182]
Further, in the sixth embodiment, the prediction correction unit may perform the prediction correction every time the color image forming apparatus is activated.
[0183]
Furthermore, in the sixth embodiment, the prediction correction unit predicts the color registration deviation amount every time the color image forming apparatus is started, and the predicted value of the color registration deviation amount exceeds a predetermined deviation amount. Alternatively, the prediction correction may be executed only on the basis of the above.
[0184]
Up to this point, the IOT main controller 71 serving as a predictive correction unit has described an example in which the start condition for predictive correction based on temperature is defined by temperature, and the color registration deviation amount associated with the temperature change amount is predicted and corrected. The correction execution timing may be specified and executed in the operation state of the image forming apparatus regardless of the temperature or in combination with the temperature prediction correction.
[0185]
That is, in the sixth embodiment, for example, in the color image forming apparatus, every time each image formation (page) is performed, or every time the machine is started (power on / polygon mirror operation start / return from the low power mode) In addition, the prediction correction operation is always performed by the prediction correction means.
[0186]
At this time, the correction amount is calculated by predicting the color registration deviation amount from the relative temperature and absolute temperature of the previous registration control operation or the predicted correction by temperature, the current temperature, and the absolute temperature, and calculating the correction value (set value). Configured.
[0187]
With this operation, the color registration misalignment prediction correction operation is always executed. Rather than operating the color registration misalignment correction (predictive correction) by setting the start condition with the above-described allowable misalignment amount, the actual registration misregistration operation is performed. It is possible to suppress the shift to a small extent. In particular, this is effective when the calculation speed of the IOT main controller 71 as the prediction correction means is high.
[0188]
At this time, if the temperature change amount is small, the predicted deviation amount and the correction amount corresponding thereto are also small. A specified value (allowable amount) is set here, and if the deviation amount or the correction amount exceeds this prescribed value, the correction is executed, and if the deviation amount or the correction amount is within this prescribed value, the correction is not performed. You may comprise. This is particularly effective when the processing is to delay the image output for the prediction operation depending on whether the operation speed of the control circuit is fast or slow.
[0189]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0190]
Embodiment 7
FIG. 34 shows a seventh embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment, and in this seventh embodiment, in a plurality of image forming units. Predictive correction means for predicting and correcting the color registration misalignment amount is provided, and the predictive correction means integrates activation of the color image forming apparatus every time a predetermined time elapses after activation of the color image forming apparatus. The color registration deviation amount is predicted and corrected based on time. In FIG. 34, the two black circles are shown separately for convenience, but the upper black circle indicates the same temperature as the lower black circle.
[0191]
In the seventh embodiment, the number of recording media accumulated in the color image forming apparatus each time the predictive correcting unit forms an image on a predetermined number of recording media after starting the color image forming apparatus. The color registration misalignment amount prediction correction may be executed based on the above.
[0192]
That is, in the seventh embodiment, when the color registration deviation characteristic does not depend on the reading temperature of a specific temperature sensor, the prediction correction operation is executed at a predetermined time interval or every number of output sheets.
[0193]
More specifically, in the case of the ROS 14 and the fixing device 37 shown in FIG. 3 and the ROS 230 and the fixing device 270 shown in FIG. When the fixing device 270 is started (at the time of temperature rise), as shown in FIG. 34, the change in color registration deviation due to the temperature rise characteristic in the apparatus deviates from the color registration characteristic for the reading temperature value of one temperature sensor. There is. This is because the temperature of a specific portion (polygon motor or fixing device) rises greatly when the polygon motor of ROS 14 or ROS 230 is started or when the fixing device 37 or fixing device 270 is started.
[0194]
Therefore, if an image forming member is present in the vicinity of the polygon motor of the ROS 14 or ROS 230, or the fixing device 37 or the fixing device 270, the image forming member is affected by the temperature rise at a specific portion, as shown in FIG. In other words, the change in color registration shift due to the temperature rise characteristic in the apparatus may deviate from the color registration characteristic for the reading temperature value of one temperature sensor.
[0195]
The temperature sensor (environment sensor) has a relatively stable color registration shift amount relative to the reading temperature value and a high color registration change sensitivity ("temperature change amount / unit color register change amount" is large). It is common to install in a specific place in the plane. However, with one temperature sensor (environment sensor), it may be difficult to cover all cases of temperature distribution in the machine. For example, the color registration deviation characteristic with respect to the reading value of one sensor may deviate like the temperature change at the time of starting the polygon mirror of ROS14 or ROS230. In other words, when the temperature sensor is installed at a location distant from the ROS 14 or ROS 230, it is a case where the temperature change in the apparatus due to the temperature rise of the ROS 14 or ROS 230 cannot be detected.
[0196]
FIG. 34 shows how the absolute temperature and color registration deviation change at this time. When the polygon mirror is activated for a certain period of time (area A in the figure), for example, when about 100 to 500 sheets are printed continuously, as shown in the upper graph of FIG. Then, the color registration shift characteristic is obtained by adding another characteristic to the color registration change characteristic (a portion indicated by hatching in FIG. 34). After a predetermined time has elapsed since the polygon mirror was activated, the color registration temperature characteristic curve returns to the in-machine temperature.
[0197]
Therefore, in the period of the area A, not only the color registration deviation prediction correction due to the temperature but also the correction amount obtained by adding the color registration deviation predicted from the polygon motor activation time may be corrected. Here, it has been described that the color registration is predicted based on the time after the polygon motor is activated. Further, here, the color registration misalignment prediction correction for a certain period after the polygon motor is started has been described. However, as a cause of occurrence, even when the fixing device 37 and the fixing device 270 are considered to be similar, Color registration misalignment prediction correction may be performed according to time or the number of output images.
[0198]
At that time, the IOT main controller 71 as the prediction correction means executes the prediction correction operation every time a predetermined time elapses from the startup time of the polygon motor or every time an image is formed on a predetermined number of recording media. Here, the predetermined time or the predetermined number of images does not need to be a constant value, and as shown in FIG. 34, there is a region where the color registration deviation changes abruptly from the startup time of the polygon motor. Alternatively, the prediction correction may be performed at a certain small time or number interval, and thereafter the prediction correction may be performed at a large time or number interval in an area where the color registration deviation is substantially flat.
[0199]
Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
[0200]
In the above embodiment, the color registration misalignment amount is predicted and the misalignment amount is corrected. However, the color registration misalignment amount is not predicted and calculated, but the correction amount for correcting the misregistration amount is predicted and calculated. May be corrected.
[0201]
【The invention's effect】
As described above, according to the present invention, it is possible to perform the registration control operation for correcting the color registration shift caused by the temperature rise in the apparatus main body, thereby making it impossible to perform the image forming operation. To provide a color image forming apparatus capable of reducing so-called downtime, reducing toner consumption for forming a registration patch, reducing a load on a cleaning member, and further reducing a waste toner collection capacity. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a tandem digital color printer as a color image forming apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing a control circuit of a tandem type printer as a color image forming apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a block diagram showing a tandem digital color printer as a color image forming apparatus according to Embodiment 1 of the present invention.
FIGS. 4A and 4B are explanatory diagrams respectively showing magnification deviations in the main scanning direction.
FIGS. 5A and 5B are explanatory diagrams showing margin shifts in the main scanning direction, respectively.
6 (a) and 6 (b) are explanatory diagrams showing skew deviations, respectively.
FIGS. 7A and 7B are explanatory diagrams showing margin shifts in the sub-scanning direction, respectively.
FIG. 8 is an explanatory diagram showing periodic fluctuations in the sub-scanning direction.
FIG. 9 is an explanatory diagram showing periodic fluctuations in the main scanning direction.
FIG. 10 is an explanatory diagram showing color registration misalignment due to various factors.
FIG. 11 is a configuration diagram showing an arrangement of a color registration error detection pattern and detection means.
FIG. 12 is an explanatory diagram showing a color registration misalignment detection pattern.
FIG. 13 is an explanatory diagram showing a color registration misalignment detection pattern.
FIG. 14 is a perspective configuration diagram illustrating a color registration error detection pattern detection unit.
FIG. 15 is an explanatory diagram illustrating a method for detecting a color registration misalignment detection pattern.
FIGS. 16A to 16C are explanatory diagrams showing main scanning coarse margin correction, sub-scanning coarse margin correction, and skew correction methods, respectively.
FIGS. 17A and 17B are explanatory diagrams showing main scanning fine margin correction, sub-scanning fine margin correction, and skew correction methods, respectively.
FIGS. 18A to 18C are explanatory diagrams showing a method of magnification balance deviation and magnification balance correction, respectively.
FIG. 19 is a waveform diagram showing clock signals used for magnification balance correction.
FIG. 20 is an explanatory diagram illustrating a method of correcting pixel positions in the main scanning direction and the sub-scanning direction.
FIG. 21 is a flowchart showing the operation of the color image forming apparatus according to Embodiment 1 of the present invention.
22A and 22B are a graph showing a color registration characteristic curve and a chart showing a temperature range based on the graph.
FIGS. 23A and 23B are graphs showing color registration characteristic curves and correction parameters based on the graphs according to Embodiment 2 of the present invention.
FIG. 24 is a graph showing a function approximating a color registration characteristic curve used for control of the color image forming apparatus according to Embodiment 3 of the present invention.
FIG. 25 is a graph showing a function that approximates a color registration characteristic curve used for control of a color image forming apparatus according to Embodiment 3 of the present invention.
FIG. 26 is a schematic diagram showing a tandem type digital color printer as a color image forming apparatus according to Embodiment 4 of the present invention.
FIG. 27 is an explanatory diagram showing a color registration misalignment detection pattern.
FIG. 28 is a sectional configuration diagram showing a sensor for detecting a color registration misalignment detection pattern.
FIG. 29 is an explanatory diagram showing a sensor for detecting a color registration misalignment detection pattern.
FIG. 30 is a schematic configuration diagram showing another configuration example of the tandem type digital color printer as the color image forming apparatus according to the first embodiment of the present invention.
FIG. 31 is a block diagram showing a conventional color image forming apparatus.
FIG. 32 is a perspective configuration diagram showing a pattern used for registration misalignment in a conventional color image forming apparatus.
FIG. 33 is a graph showing the operation of the color image forming apparatus according to Embodiment 5 of the present invention.
FIG. 34 is a graph showing the operation of the color image forming apparatus according to Embodiment 7 of the present invention.
[Explanation of symbols]
1: printer main body, 13K, 13Y, 13M, 13C: image forming unit, 14: ROS, 25: intermediate transfer belt, 50: pattern for color registration misalignment detection, 60: detection means, 71: IOT main controller (prediction Correction means).

Claims (1)

A plurality of image forming units that form images having different colors from each other, and transferring images having different colors formed by the plurality of image forming units onto a recording medium directly or via an intermediate transfer member, In a color image forming apparatus for forming a color image, a temperature detection unit that detects a temperature in the color image forming apparatus main body, and the plurality of image formations based on the temperature in the apparatus main body detected by the temperature detection unit Predictive correction means for predicting and correcting the color registration misalignment amount in the unit,
The color registration misalignment detection pattern formed by each image forming unit is transferred onto the same pattern detection member, and the color registration misalignment detection pattern transferred onto the pattern detection member is detected, and the color is detected. A registration error correction operation executing means for executing a registration error correction operation, wherein the prediction correction means performs at least one color registration error amount while the registration error correction operation is executed by the registration error correction operation execution means. While performing the prediction correction operation,
The prediction correction means uses the temperature in the apparatus main body when the registration deviation correction operation is executed by the registration deviation correction operation execution means as a reference temperature, and registers the absolute temperature in the apparatus main body and an allowable maximum registration deviation amount. Using the temperature parameter table in which the temperature difference from the temperature at which the deviation occurs is stored in advance, set a condition temperature for performing the prediction correction according to the reference temperature,
A color image in which a prediction correction operation is executed each time the temperature in the apparatus main body detected by the temperature detection means reaches a temperature set as a condition temperature for executing the prediction correction in accordance with the reference temperature. Forming equipment.

Images