JP2003149904A - Color image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image forming apparatus in which the reduction of states where an image forming action is impossible, the reduction of so-called down time, the reduction of toner consumption for registration control patch formation, the reduction of a load to a cleaning member, and the reduction of an amount, etc., of discard toner to be recovered are achieved by efficiently carrying out a registration control action to correct a color registration deviation caused by a temperature rise in an apparatus main body. SOLUTION: The color image forming apparatus is provided with a corrective operation performance means for a registration deviation which transfers a pattern for a registration deviation detection formed by each image forming unit on the same patterns detection member, detects the pattern for the registration deviation detection transferred on the pattern detection member to carry out a registration deviation corrective operation, a temperature detecting means which detects a temperature within the main body of the color image forming apparatus, and a corrective operation determination means for the registration deviation to determine the start conditions of the registration deviation corrective operation at intervals of changing temperatures according to the detected value of the temperature in the apparatus main body detected by the temperature detecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 a so-called tandem type color image forming apparatus including a plurality of image forming units that form images of mutually different colors, a registration (hereinafter, referred to as an image forming position of each color image formed by the plurality of image forming units). (Registration is also simply referred to as "register").

[0002]

2. Description of the Related Art Conventionally, there is, for example, a so-called tandem type color image forming apparatus having a plurality of image forming units of this type as shown in FIG. As shown in FIG. 30, this tandem-type color image forming apparatus includes four image forming units 100 that form toner images of different colors such as yellow, magenta, cyan, and black.
Y, 100M, 100C, 100K, and these image forming units 100Y, 100M, 100C, 100
The Ks are arranged in parallel at regular intervals along the horizontal direction. The above four image forming units 100
Y, 100M, 100C, and 100K have the same configuration except that the color of the toner image to be formed is different,
After the surface of the photoconductor drum 101 is uniformly charged by the contact type charging device 102, the surface of the photoconductor drum 101 is subjected to image exposure by the exposure device 103, and an electrostatic latent image corresponding to the image information of each color. To form. The electrostatic latent image formed on the surface of the photosensitive drum 101 is visualized as a toner image by the developing device 104 of the corresponding color, and the toner image is transferred by the charger 105 for primary transfer to the intermediate transfer belt. It is transferred onto 106 in sequence. 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 step.

The intermediate transfer belt 106 includes four image forming units 100Y, 100M, 100C and 100K.
A plurality of rollers 108 to 111 including driving rollers are circulated and driven at a speed equal to the rotation speed of the photosensitive drum 101. The yellow, magenta, cyan, and black toner images sequentially and multiply transferred onto the intermediate transfer belt 106 are transferred to the intermediate transfer belt 10 at a secondary transfer position below the intermediate transfer belt 106.
By the secondary transfer roll 112 that comes into contact with the surface of the sheet 6, the images are collectively transferred onto the recording paper 113 fed at a predetermined timing. After that, the recording paper 113 is conveyed to the fixing device 114, undergoes a fixing process by heat and pressure by the fixing device 114, is discharged to the outside of the device, and a full-color or monochrome image is formed.

By the way, in such a tandem type color image forming apparatus, a plurality of image forming units 100Y and 10Y are provided.
A plurality of image forming units 100Y, 100M, 100C are controlled by controlling an image forming position of each color image formed by 0M, 100C, 100K, that is, registration.
A registration control technique is adopted in which the registrations of the images of the respective colors formed at 100K are accurately matched with each other.

An example of an image forming apparatus adopting this registration control technique is, for example, JP-A-1-142674 and JP-A-1-142.
As disclosed in Japanese Unexamined Patent Application Publication No. 680, JP-A-1-183676, etc., as shown in FIG. 31, ROS of each image forming unit 100Y, 100M, 100C, 100K.
A predetermined image position recognition pattern 120 is formed on the photoconductor drum 101 by 103, and the image position recognition pattern 120 of each color formed on each photoconductor drum 101 is transferred to the intermediate transfer belt 106. First, the images are sequentially primary-transferred to the upper side, sampled by the CCD 121 arranged on the downstream side of the final stage image forming unit 100K, and the color shift of the image position recognition pattern 120 of each predetermined color is determined according to the positional relationship of the sampling data. It is detected how much difference there is from the positional relationship on the assumption that there is no difference, and the registration deviation (hereinafter referred to as “registration deviation”) amount of each color is calculated from the detected data.
In the image forming apparatus, each image forming unit 1
ROS103 of 00Y, 100M, 100C, 100K
There is proposed a method of providing high-quality image with less misregistration by correcting the writing timing or the position of an optical system component.

The image position recognition pattern 120 of each color transferred onto the intermediate transfer belt 106 is removed by a cleaning device 115 for cleaning the surface of the intermediate transfer belt 106.

Techniques relating to this registration control device include, for example, JP-A-1-142674, JP-A-1-142680, and JP-A-1-183.
Some are disclosed in Japanese Patent No. 676, etc.

Further, as a technique for correcting the deterioration of the color registration deviation amount due to the temperature rise in the machine, those disclosed in Japanese Patent No. 2625130 and Japanese Patent No. 2921856 have been already proposed. .

The techniques disclosed in Japanese Patent No. 2625130 and Japanese Patent No. 2921856 are such that when the temperature rise inside the machine changes by a predetermined temperature after the power is turned on or the registration control is performed, or the previous registration control is performed. The register control sequence is operated when the predetermined temperature changes by a predetermined temperature.

To explain further, the above-mentioned Japanese Patent No. 2525
The image forming apparatus according to No. 130 has a plurality of image stations each having an image carrier, a moving body that moves to transfer each image formed on the plurality of image carriers at a transfer position, and A reading unit for reading each registration mark image formed by a plurality of image stations and transferred onto the moving body, and a positional deviation between the images formed by the plurality of image stations based on the reading result of the reading unit. Correction means for correcting the temperature, temperature detection means for detecting the temperature inside the apparatus, the plurality of image stations form the registration mark image and transfer each registration mark image onto the moving body, and the reading means Each of the registration mark images transferred on the moving body is read, and the correction means performs the correction operation based on the read result. And control means for controlling on the basis of the execution of the registration correction sequence to an output of said temperature detecting means,
It is configured to include.

The color image forming apparatus according to Japanese Patent No. 2921856 has an endless conveying means for conveying the transfer material, and the transfer material is arranged at a predetermined interval along the moving direction of the endless conveying means. In a color image forming apparatus having a plurality of image recording means for sequentially recording images of different colors, a temperature detecting means for detecting the temperature inside the apparatus, and a temperature detected by the temperature detecting means is increased every predetermined temperature. A control means for forming a detection pattern corresponding to each color on the endless conveying means by the plurality of image forming means, a pattern detection means for detecting the detection pattern, and a detection result by the pattern detection means. A correction processing unit that calculates the positional deviation amount of each color and corrects the positional deviation amount of each color is configured.

On the other hand, the condition for starting the register control is not the temperature inside the machine, but the continuous device operating time from the time the power is turned on,
A technique of gradually extending the interval of the registration control sequence according to the operation time is also disclosed in Japanese Patent Laid-Open No. 5-188697.
It has already been proposed as disclosed in Japanese Patent Publication No.

The image forming apparatus according to Japanese Patent Laid-Open No. 5-188697 discloses a plurality of image forming means for sequentially superposing images of a plurality of colors on a common recording medium, and each color formed by the image forming means. In an image forming apparatus having a correction unit that corrects a positional deviation between images and a control unit that controls a timing of executing a correction process by the correction unit, a predetermined time has passed after the power of the image forming apparatus main body is turned on. The control means is configured to gradually lengthen the interval at which execution of the correction processing is started during the period.

[0014]

However, the above-mentioned prior art has the following problems. That is, the above-mentioned Japanese Patent No. 2625130 and Japanese Patent No. 2921.
In the case of the technique disclosed in Japanese Patent Publication No. 856, the execution of the resist correction sequence is controlled based on the output of the temperature detecting means, or the temperature detected by the temperature detecting means for detecting the temperature inside the apparatus is Every time the temperature rises,
The plurality of image forming units are configured to form a detection pattern, and to detect and correct the detection pattern.

However, in the above image forming apparatus,
Depending on the frequency of image forming operations and the contents of the image forming operations to be performed, the temperature rise inside the machine is not uniform, and the change characteristic of the color registration deviation with respect to the temperature inside the machine is not linear. When the execution of the sequence is controlled based on the output of the temperature detection means, or the color registration misregistration correction operation is performed every time the temperature inside the machine rises by a predetermined temperature, pattern formation or unnecessary The detection operation has been executed and the image forming operation cannot be performed due to the registration control sequence operation. The frequency of so-called downtime, the toner consumption amount for forming the registration control patch, or the load on the cleaning member. There is a problem that it causes an unnecessary increase in the waste toner recovery capacity and the like.

Further, in the case of the image forming apparatus according to the above-mentioned Japanese Patent Laid-Open No. 5-188697, the start condition of the register control is not the temperature inside the machine but the continuous apparatus operation time from the power-on, and the operation time is According to the configuration, the interval of the register control sequence is gradually extended.However, even in this case, the continuous operation time of the device from the time of power-on depends on the device down time, etc. Unlike the time when the image was formed, it does not correlate with the temperature rise inside the machine, and again the pattern formation and the detection operation are unnecessarily executed, and due to the registration control sequence operation, Inability to perform image forming operation Frequency of so-called downtime, toner consumption for registration control patch formation, load on cleaning member, and It has a problem of causing an unnecessary increase in such toner recovery capacity.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art, and its object is to perform a registration control operation for correcting a color registration shift caused by a temperature rise in the apparatus main body. By making it possible to efficiently perform the above, it is possible to reduce the so-called downtime in which the image forming operation is impossible, reduce the toner consumption for forming the registration control patch, or reduce the load on the cleaning member. Is to provide a color image forming apparatus capable of reducing the amount of waste toner collected.

Another object of the present invention is to correct the registration control if the downtime, the toner consumption amount for forming the registration control patch, the load on the cleaning member, etc. are the same as those of the conventional apparatus. It is to provide a color image forming apparatus capable of further improving accuracy.

[0019]

In order to solve the above-mentioned problems, the invention described in claim 1 is provided with a plurality of image forming units for forming images of mutually different colors. In a color image forming apparatus that forms a color image by transferring formed images of different colors onto a recording medium directly or via an intermediate transfer member, detecting a registration deviation formed by each of the image forming units. A registration deviation correction operation executing unit that transfers the registration pattern onto the same pattern detection member, detects the registration deviation detection pattern transferred onto the pattern detection member, and executes the registration deviation correction operation, The temperature detecting means for detecting the temperature in the main body of the color image forming apparatus and the temperature detecting means for changing the temperature in the main body of the apparatus detected by the temperature detecting means. Temperature interval is obtained by configured with the registration deviation correcting operation determining means for determining a condition for starting the misregistration correction operation in the.

Here, the "registration shift correction operation" means an operation of forming a registration shift detection pattern, detecting the registration shift detection pattern, and correcting the registration shift.

The "pattern detecting member" may be, for example, an image formed by each image forming unit.
Although an intermediate transfer member for primary transfer is used, the present invention is not limited to this, and a recording medium conveying member such as a belt for conveying a recording medium, or a plurality of images transferred in multiple on the intermediate transfer member is used. Alternatively, it may be a transfer member or the like for final transfer onto a recording medium.

According to a second aspect of the present invention, in the color image forming apparatus according to the first aspect, the registration deviation correction operation determining means is inside the apparatus main body detected by the temperature detecting means. Corresponding to the detected value of each temperature, there is a temperature interval that determines whether the registration shift correction operation is started when the temperature in the main body of the apparatus changes.
Moreover, the temperature interval is set to a different value according to the detected value of the temperature inside the apparatus body.

Further, the invention described in claim 3 is the color image forming apparatus according to claim 2, wherein
Corresponding to the detected value of each temperature in the apparatus main body detected by the temperature detecting means, a temperature interval for deciding whether to start the registration deviation correction operation when the temperature in the apparatus main body changes. The start temperature interval table stored in advance is provided.

According to a fourth aspect of the invention, in the color image forming apparatus according to the second aspect of the invention, the color image forming apparatus corresponds to the detected value of each temperature in the apparatus main body detected by the temperature detecting means. It is configured to include an arithmetic expression for obtaining a temperature interval for determining whether to start the registration shift correction operation when the temperature inside the apparatus main body changes.

Further, according to the invention described in claim 5, in the color image forming apparatus according to any one of claims 1 to 4, each time the registration deviation correction operation is executed, the next registration deviation correction operation is performed. It is configured to determine the upper limit value and the lower limit value of the temperature interval to be executed.

According to a sixth aspect of the present invention, in the color image forming apparatus according to the second aspect, the temperature interval for deciding whether to start the registration deviation correction operation is stored as a fixed value. It is configured to have at least one temperature interval table.

Furthermore, the invention described in claim 7 is
The color image forming apparatus according to claim 2, wherein the temperature interval that determines whether to start the registration shift correction operation has at least one temperature interval arithmetic expression that determines a fixed value. is there.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

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. Further, this tandem type digital color printer is equipped with an image reading device, and also functions as a full-color copying machine. The digital color printer may of course be provided with no image reading device and form an image based on image data output from a personal computer or the like (not shown). The digital color printer may also have a function as a facsimile.

In FIG. 2, reference numeral 1 denotes a main body of a tandem type digital color printer (color image forming apparatus). This digital color printer main body 1 reads an image of an original 2 on an upper part of one end side thereof. Image reading device (IIT: Image Input Terminal)
l) 4 is provided and image data output from the image reading device 4 or a personal computer (not shown) or the like is sent to the inside of the digital color printer body 1 via a telephone line, a LAN, or the like. An image processing apparatus (IPS: which performs predetermined image processing on image data)
Image Processing System) 1
2 and an image output device (IOT: Image Output Terminal) that outputs an image based on image data subjected to predetermined image processing by the image processing device 12.
l) 100 are provided.

Inside the digital color printer main body 1, as image forming units constituting the image output apparatus 100, black (K), yellow (Y), magenta (M),
Cyan (C) image forming units 13K and 13
Y, 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 body that transfers the toner images of the respective colors sequentially formed by these image forming units in a state of being superposed on each other. The transfer belt 25 is disposed so as to be rotatable in the arrow direction. Then, the intermediate transfer belt 25
The toner images of the respective colors, which are transferred in multiple layers on the upper side, are fed to the paper feed tray 3
After being collectively transferred onto a recording sheet 34 as a recording medium fed from the recording sheet 9 or the like, the recording sheet 3 is fixed by the fixing device 37.
It is fixed on the sheet 4 and discharged to the outside.

In the embodiment shown in FIG. 2, the image output device 100 is configured so that each image forming unit 13K, 13Y,
After the toner images of black (K), yellow (Y), magenta (M), and cyan (C) formed of 13M and 13C are primary-transferred on the intermediate transfer belt 25 in a state of being superimposed on each other, The case where the color image is formed by collectively performing the secondary transfer on the recording paper 34 from the intermediate transfer belt 25 has been described.
Not limited to this, as shown in FIG. 23, as shown in FIG. 23, black (K), yellow (Y), magenta (M) formed by the image forming units 13K, 13Y, 13M, and 13C,
A toner image of each color of cyan (C) is transferred onto the recording sheet 34 conveyed by a sheet conveying belt 25 'serving as a recording medium conveying member in a state of being superimposed on each other to form a color image. Of course, it can also be applied to the above. In addition, each image forming unit 1
The order of colors of 3K, 13Y, 13M, and 13C is not limited to black (K), yellow (Y), magenta (M), and cyan (C), but yellow (Y), magenta (M). Of course, the order of cyan, cyan (C) and black (K) may be arbitrary.

FIG. 3 shows the structure of a tandem type digital color printer as an image forming apparatus according to the first embodiment of the present invention in more detail.

Although the configuration of the present invention will be described here using a tandem type digital color printer, the present invention is also effective in a color copying machine / facsimile or the like. The same applies to the following embodiments.

In FIG. 3, reference numeral 1 denotes a main body of a tandem type digital color printer, and a platen cover 3 for pressing an original 2 onto a platen glass 5 is provided on an upper portion of one end side of the digital color printer main body 1. An image reading device 4 for reading an image of the document 2 placed on the platen glass 5 is provided. This image reading device 4
Illuminates the original 2 placed on the platen glass 5 with the light source 6, and reflects the reflected light image from the original 2 on the full rate mirror 7, the half rate mirrors 8 and 9, and the imaging lens 1.
Scanning exposure is performed on an image reading element 11 such as a CCD via a reduction optical system including 0, and the color material reflected light image of the original 2 is scanned by the image reading element 11 at a predetermined dot density (for example, 16 dots / mm). ) Is configured to read.

The color material reflected light image of the original 2 read by the image reading apparatus 4 is, for example, original reflectance data of three colors of red (R), green (G), blue (B) (each 8 bits). As the image processing apparatus 12 (Image Proce
The image processing device 12 sends predetermined data such as shading correction, positional deviation correction, lightness / color space conversion, gamma correction, frame erasing, color / moving editing, etc. to the reflectance data of the original 2. Image processing is performed.

The image data which has been subjected to the predetermined image processing by the image processing apparatus 12 as described above has four colors of yellow (Y), magenta (M), cyan (C) and black (K) (each 8 bits). The image forming units 13K and 13Y of the respective colors of black (K), yellow (Y), magenta (M), and cyan (C) are converted into the color original color material gradation data (raster data) as described below. , 13M, 13C ROS
14K, 14Y, 14M, 14C (Raster Ou
tputScanner) to send these ROS
In 14K, 14Y, 14M, and 14C, image exposure with laser light is performed according to image data of a predetermined color.

By the way, inside the tandem type digital color printer main body 1, as described above, four image forming units 13K for black (K), yellow (Y), magenta (M) and cyan (C) are provided. , 13Y, 13
M and 13C are arranged in parallel in the horizontal direction at regular intervals.

These four image forming units 13K,
13Y, 13M, and 13C have the same structure except that the colors of images to be formed are different, and are roughly classified into a photosensitive drum 15 as an image carrier that rotates at a predetermined rotation speed in the arrow direction. A primary charging scorotron 16 as a charging means for uniformly charging the surface of the photoconductor drum 15 and an image corresponding to each color are exposed on the surface of the photoconductor drum 15 to form an electrostatic latent image. The image forming apparatus includes a ROS 14, a developing device 17 for developing the electrostatic latent image formed on the photoconductor drum 15, and a cleaning device 18.

As shown in FIG. 3, the ROS 14 modulates the semiconductor laser 19 according to the image data of each color and emits the 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 passes through the reflection mirror 21 and a plurality of reflection mirrors 23 and 24 to the photosensitive drum 15. Scanned and exposed on top.

From the image processing device 12, black (K),
The image data (raster data) of each color is sequentially output to the ROSs 14K, 14Y, 14M, and 14C of the image forming units 13K, 13Y, 13M, and 13C of yellow (Y), magenta (M), and cyan (C), respectively. ROS
A laser beam LB emitted from 14K, 14Y, 14M, and 14C according to image data is scanned and exposed on the surface of each photoconductor drum 15K, 15Y, 15M, and 15C to form an electrostatic latent image. Each photoconductor drum 1
The electrostatic latent images formed on 5K, 15Y, 15M and 15C are developed by the developing devices 17K, 17Y, 17M and 17C.
Black (K), yellow (Y), magenta (M),
It is developed as a toner image of each color of cyan (C).

The image forming units 13K, 13Y,
13M, 13C photoconductor drums 15K, 15Y, 15
The toner images of black (K), yellow (Y), magenta (M), and cyan (C), which are sequentially formed on M and 15C, are respectively formed in the image forming units 13K, 13Y, 13M, and 1.
The primary transfer rolls 26K, 26Y, and 26 are provided on the intermediate transfer belt 25 as an intermediate transfer body, which is disposed below 3C.
Multiple transcription by M and 26C. The intermediate transfer belt 25 includes a drive roll 27 and an idle roll 2
8, steering roll 29, idle roll 30
, A backup roll 31 and an idle roll 32 are wound around with a constant tension, and are driven in a predetermined direction in an arrow direction by a drive roll 27 which is rotationally driven by a dedicated drive motor (not shown) having excellent constant speed. It is designed to be circulated at the speed of. As the intermediate transfer belt 25, for example, a synthetic resin film having flexibility such as polyimide is formed into a strip shape, and both ends of the synthetic resin film formed into the strip shape are connected by welding or the like to form an endless belt. A belt-shaped member is used.

The toner images of the respective colors of black (K), yellow (Y), magenta (M), and cyan (C) transferred in multiple layers on the intermediate transfer belt 25 are backup rolls 31.
The recording sheet 34 is secondarily transferred onto the recording sheet 34 by a pressing force and an electrostatic force by the secondary transfer roll 33 that is pressed against the recording sheet 34, and the recording sheet 34 to which the toner images of the respective colors are transferred is fixed by the two conveyor belts 35 and 36. It is conveyed to the container 37. The recording paper 34 onto which the toner images of the respective colors have been transferred is
The fixing device 37 receives the fixing process with heat and pressure, and the sheet is discharged onto a discharge tray 38 provided outside the printer body 1.

The recording paper 34, as shown in FIG.
A paper feed path 46 including a paper feed roller 42 and a pair of paper feed rollers 43, 44, 45 from a plurality of paper feed trays 39, 40, 41 having a predetermined size.
The sheets are once conveyed to the registration roll 47 via the. The recording paper 34 supplied from any one of the paper feed trays 39, 40, 41 is delivered onto the intermediate transfer belt 25 by a registration roll 47 which is rotationally driven at a predetermined timing.

Then, the four image forming units 13K and 13K for the black, yellow, magenta and cyan colors are formed.
In Y, 13M, and 13C, as described above, the toner images of black, yellow, magenta, and cyan are sequentially formed at predetermined timings.

The photosensitive drums 15K, 15Y,
15M and 15C are after the toner image transfer process is completed,
The cleaning devices 18K, 18Y, 18M, and 18C remove residual toner, paper dust, and the like to prepare for the next image forming process. Further, the intermediate transfer belt 25 is cleaned of residual toner by a cleaning device 48 for the belt and a cleaning blade or a brush.

By the way, in the tandem type digital color printer configured as described above, as shown below, due to various factors such as vibration during transportation and installation, temperature change in the machine, and the like, each image forming unit Positional fluctuations occur in the photoconductor drum, etc., causing image misregistration (registration misregistration).
Occurs.

First, the image forming units 13K and 13
In Y, 13M and 13C, photosensitive drums 15K and 1K
If the positions of 5Y, 15M, and 15C are misaligned, the distance (optical path length) between the ROS 14K, 14Y, 14M, and 14C and the photoconductor drums 15K, 15Y, 15M, and 15C changes as shown in FIG. The deviation of the magnification in the direction (laser beam scanning direction) and the deviation of the magnification in the left and right directions in the main scanning direction occur. The image forming units 13K, 13Y,
ROS 14K, 14Y, 14 at 13M, 13C
M, 14C and photoconductor drums 15K, 15Y, 15M, 1
If there is a positional shift along the main scanning direction in 5C, a margin shift in the main scanning direction occurs as shown in FIG.

Further, each image forming unit 13K, 13
In Y, 13M, and 13C, as shown in FIG. 6, when the rotation axes of the photoconductor drums 15K, 15Y, 15M, and 15C are inclined, skew deviation occurs. Further, when the photosensitive drums 15K, 15Y, 15M, and 15C have a positional deviation along the sub-scanning direction as shown in FIG. 7, a deviation of the margin in the sub-scanning direction occurs.

In addition to the above registration shift, in each of the image forming units 13K, 13Y, 13M and 13C,
As shown in FIG. 8, the photosensitive drums 15K, 15Y, 15
If there are speed fluctuations in M, 15C and the intermediate transfer belt 25,
Periodic fluctuations in the sub-scanning direction (AC fluctuations) occur, which causes color registration deviations (hereinafter referred to as “color registration deviations”) between different colors. Further, when the intermediate transfer belt 25 has a meander in the main scanning direction, as shown in FIG. 9, a periodic fluctuation (AC fluctuation) in the main scanning direction occurs, which causes a color registration shift between different colors. Occurs.

As described above, due to various factors, the magnification deviation in the main scanning direction, the lateral magnification deviation in the main scanning direction, the skew deviation, the sub scanning margin deviation, the main scanning margin deviation, the sub scanning periodic deviation, Scan periodic deviation occurs,
As shown in FIG. 10, when the positional deviations of these images are superimposed, a DC-like deviation (uniform deviation) or an AC-like deviation (periodic deviation) occurs, resulting in a color registration deviation.

Therefore, in this embodiment, as shown in FIG. 11, a pattern 50 for detecting color registration deviation is formed on the intermediate transfer belt 25 at a predetermined timing, and the pattern 50 for detecting color registration deviation is formed. The image forming units 13K, 13Y, and
A color shift image is formed after the registration shift correction operation for correcting the color shifts of 13M and 13C is executed. The detecting means 60 are arranged at both ends along the width direction of the intermediate transfer belt 25, for example, but if necessary, both ends and the center thereof along the width direction of the intermediate transfer belt 25. A plurality (three or more) may be provided at equal intervals along the width direction of the portion or the intermediate transfer belt 25, and are appropriately arranged according to the type of color registration deviation to be detected.

As shown in FIGS. 12 and 13, the color registration shift detection pattern 50 includes a first chevron mark 51KK made of a first reference color and a second chevron mark made of a second measured color. The pattern in which all the measured colors are combined is used with the mountain-shaped mark 51YY and the third mountain-shaped mark 51KY consisting of the first color and the second color as one unit. The combination of the patterns 50 shown in FIG. 12 is one block in the reference color and the target color.
When this pattern is actually used, as shown in FIG. 13, it is repeatedly formed for several blocks and is sampled. Here, the first embodiment of the present invention will be described on the assumption that sampling for one round of the intermediate transfer belt 25 is performed. The signal for outputting the color registration deviation detection pattern 50 is stored in advance in, for example, the ROM of the printer output control means 85 as the registration deviation correction operation execution means of the image processing apparatus 12 described later. Further, it goes without saying that the color registration shift detection pattern 50 may have another shape.

FIG. 14 is a perspective view showing the pattern detector 60 for detecting the color registration deviation.

In FIG. 14, 61 is the pattern detector 6.
0 is a housing, and 62a and 62b are intermediate transfer belts 25.
The two light emitting elements 63a and 63a respectively illuminate the pattern 50 for detecting the color registration deviation formed on the upper side.
Reference numerals b, 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 shift detection pattern 50 formed on the intermediate transfer belt 25. The two sets of light receiving elements 63a, 63b and 64a, 64b are arranged as shown in FIG. The two light emitting elements 62
As the a and 62b, for example, an LED or the like that emits light of a specific wavelength or light having a predetermined wavelength distribution is used, and these light emitting elements 62a and 62b are located at one detection position on the intermediate transfer belt 25. Are arranged so as to illuminate each other from a diagonal direction on the opposite side which is inclined by a predetermined angle. The two sets of light receiving elements 63a, 63b and 64a, 64b are arranged such that their central portions face each other or contact each other, and both end portions are inclined downward by a predetermined angle with respect to the horizontal direction. Elements 63a, 63b and 6
4a, 64b, and the light receiving elements 63a, 63
As shown in FIG. 12, b, 64a, and 64b are set so that the detection timing and the detection angle of the reflected light are different from each other.

As shown in FIG. 15, when the pattern detector 60 detects the color registration deviation detection pattern 50 formed on the intermediate transfer belt 25, the linear mark of the color registration deviation detection pattern 50 is detected. As shown in FIG. 15A, one of the light receiving elements 63b outputs a smooth mountain-shaped waveform first, and after a slight delay, the other light receiving element 63a also outputs the waveform shown in FIG. ), A smooth mountain-shaped waveform is output. And
By amplifying the waveforms output from these two light receiving elements 63b and 63a and then taking the difference, or by taking the difference and then amplifying it, the waveform temporarily falls into a large mountain shape as shown in FIG. 16 (c). Then, an output waveform that rises in a large mountain shape can be obtained. Therefore, by taking the difference between the waveforms output from the two light receiving elements 63a and 63b, it is possible to use a highly accurate sensor such as a CCD,
As shown in FIG. 15D, the linear mark 51 of the color registration shift detection pattern 50 can be detected with high resolution and high accuracy.

Using the color registration shift detection pattern 50 as described above, the image forming units 13K, 13Y, 13M, 1 for black, yellow, magenta and cyan are formed.
The misregistration of each color toner image formed in 3C is detected.

Then, in the tandem type digital color printer according to this embodiment, each image forming unit forms a toner image of each color detected by using the color registration deviation detection pattern 50. The operation of correcting the position of the image to be performed is performed. It should be noted that the calculation of the correction amount and the correction operation 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 are performed. For example, this is performed by the printer output adjusting means 74 described later.

First, in order to correct the coarse margin in the main scanning direction, as shown in FIG. 16A, the ROSs 14K and 14 of the image forming units 13K, 13Y, 13M and 13C, respectively.
Y, 14M, 14C, the photosensitive drums 15K, 15Y,
When exposing an image on 15M and 15C, the recording start position of the image in the main scanning direction is SOS (Start Of
Scan) is determined by the rising edge of the signal
By changing the count number of VCLK, which is a clock signal from the rise of the OS signal to the activation of the LS (Line Sync) signal, which is the enable signal for actual image exposure, in the main scanning direction in units of 1 VCLK (pixel) It is possible to correct the recording start position of the image in.

To correct the coarse margin in the sub-scanning direction, as shown in FIG. 16A, the ROSs 14K and 14 of the image forming units 13K, 13Y, 13M and 13C are used.
Y, 14M, 14C, the photosensitive drums 15K, 15Y,
When an image is exposed on 15M and 15C, the recording start position of the image in the sub-scanning direction is determined by the rising edge of the TR0 signal, but from the rising edge of the TR0 signal, the PS (Page) which is an enable signal for actual image exposure.
1) by changing the count number of SOS which is a clock signal until the Sync signal becomes active.
The image recording start position in the sub-scanning direction can be corrected in units of S (pixels).

Next, in order to correct the skew, FIG.
As shown in (b), ROS 14K, 14Y, 14M,
By tilting the final stage mirror 24 in 14C,
The inclination of the laser beam exposed on the photosensitive drums 15K, 15Y, 15M, and 15C is corrected.

Further, in order to correct the magnification along the main scanning direction, as shown in FIG.
The pixel width is changed by changing the frequency of the VCLK (video clock: main scanning pixel output clock) signal that determines the pixel interval when exposing an image along the main scanning direction in 4Y, 14M, and 14C. It is possible to correct the magnification along the main scanning direction.

In order to correct a minute margin along the main scanning direction, as shown in FIG.
By changing the phase of the signal, it is possible to correct a small margin of one pixel or less along the main scanning direction.

On the other hand, in order to correct a small 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. 17B. It is possible to correct a small margin below the pixel in the sub-scanning direction.

Further, as shown in FIG. 18 (a), RO
S14K, 14Y, 14M, 14C and photosensitive drum 15
When the distance between K, 15Y, 15M, and 15C is different between the IN side and the OUT side of the device, as shown in FIG. 18B, the frequency of the VCLK signal is balanced according to the deviation of the magnification balance. By changing the correction value and the inclination, the magnification balance is corrected.

To correct an arbitrary magnification (magnification / balance / partial magnification difference) deviation, as shown in FIG.
VCLK (Video clock: Main scan pixel output clock)
A signal and a plurality of pulses VCLK1 to VCLK whose phase is shifted in the same cycle are set in advance, and the plurality of pulses VCLK1 to VCLK1 to VCLK1 are set in accordance with magnification, balance (horizontal magnification difference), or partial magnification deviation. 8 is selected appropriately and VCL
By creating K, it becomes possible to correct an arbitrary magnification (magnification / balance / partial magnification difference) deviation.

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.
When the correction amount of the pixel position calculated from the shift amount corresponds to, for example, −5 pixels in the main scanning direction and +4 pixels in the sub scanning direction,
The data of the (N, M) data address is changed to (N-5, M +
4) By changing to the data address, it is possible to correct the deviation in the main scanning direction and the sub scanning direction only by processing the image data without changing the image writing clock.

When an LED bar in which LED elements are linearly arranged is used as the image exposure device instead of the ROS, the pixel output timing in the sub-scanning direction is controlled by changing the light emission timing. Is possible.

By the way, in this embodiment, the registration deviation detecting pattern formed by each image forming unit is transferred onto the same pattern detecting member, and the registration deviation detecting pattern transferred onto the pattern detecting member is detected. Misregistration correction operation execution means for detecting a registration pattern and performing a registration deviation correction operation, temperature detection means for detecting the temperature inside the color image forming apparatus main body, and inside the apparatus main body detected by the temperature detection means And a registration deviation correction operation determining unit that determines the start condition of the registration deviation correction operation at a temperature interval that changes according to the detected temperature value.

Further, in this embodiment, the registration deviation correction operation determining means determines the temperature inside the apparatus body according to the detected value of each temperature inside the apparatus body detected by the temperature detecting means. The temperature interval determines whether or not to start the registration deviation correction operation when the temperature change occurs, and the temperature interval is determined according to the detected value of the temperature in the apparatus main body.
It is configured to set different values.

Further, in this embodiment, when the temperature inside the apparatus main body changes many times in response to the detected value of each temperature inside the apparatus main body detected by the temperature detecting means, the registration deviation correction is performed. It is configured to include a start temperature interval table that stores in advance the temperature interval that determines whether to start the operation.

Further, in this embodiment, each time the registration deviation correction operation is executed, the upper limit value and the lower limit value of the temperature interval for executing the next registration deviation correction operation are determined.

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 the first embodiment of the present invention.

In FIG. 2, reference numeral 71 denotes an IOT main controller having a function as a registration deviation correction operation executing means for controlling an image forming operation in the image output apparatus 100 of the digital color printer and a registration deviation correction operation determining means, and 72 denotes an interface. The ESS 73 is an ESS to which image data is input from the image reading device 4 or a personal computer (not shown), and the ESS 73.
A RAM provided inside the printer, 75 is a temperature sensor as a temperature detecting means for detecting the temperature inside the printer body 1,
Reference numeral 76 denotes a RAM provided inside the image processing apparatus 12, 6
Reference numeral 0 denotes a pattern detector for detecting the color registration deviation detection pattern 50 formed on the intermediate transfer belt 25. The temperature sensor 75 is arranged in the central portion of the printer body 1, for example.

In the tandem type digital color printer according to the first embodiment having the above structure, the registration control operation for correcting the color registration deviation due to the temperature rise in the apparatus main body is efficiently performed as follows. By making it possible to perform the image forming operation, the so-called downtime is reduced, the toner consumption for forming the registration check patch is reduced, or the load on the cleaning member is reduced. It is possible to reduce the collection capacity.

That is, in the tandem type digital color printer according to the first embodiment, as shown in FIG. 21, the IOT main controller 71 first causes the registration shift when the power of the apparatus is turned on (step 101). It is determined whether or not it is time to execute the correction operation (step 1
02). In the first embodiment, the IOT main controller 71 is set to execute the registration deviation correction operation whenever the power of the apparatus is turned on.
Is the temperature T in the printer body 1 measured by the temperature sensor 75.
Is detected and confirmed (step 103), it is determined whether the temperature T in the printer body 1 is equal to or higher than the upper limit value Tu (T ≧ Tu) or equal to or lower than the lower limit value Tl (T ≦ Tl) (step 104). . When the power of the apparatus is turned on, the upper limit value Tu is set to a value that is always satisfied, and as described above, the registration deviation correction operation is always executed (step 105). ). Also, step 1
In 02, when it is determined that it is not the timing to execute the registration deviation correction operation, the determination is continued until the timing to execute the registration deviation correction operation.

Here, the timing for executing the registration deviation correction operation is other than when the power of the apparatus is turned on.
After a certain period of time when the device is on standby, when a print job starts, when a print job ends, after a certain number of print jobs has passed, after a certain period of time has passed during a print job, transition to sleep mode (power saving mode) When returning from sleep mode, etc.

On the other hand, the temperature T in the printer body 1 is higher than the upper limit value Tu (T ≧ Tu) or lower than the lower limit value Tl (T ≦ T).
If it is not Tl), the process returns to step 102.

Next, the IOT main controller 71
A registration shift correction operation is executed (step 105).

In this registration misregistration correction operation, a pattern 50 for color registration misregistration detection as shown in FIG. 12 is formed on the intermediate transfer belt 25, and the pattern 50 for color registration misregistration detection is detected by the pattern detector 60. Detected by
The registration control operation is executed.

The position data of the pattern 50 for detecting the color registration shift detected by the pattern detector 60 is shown in FIG.
As shown in FIG. 3, the image forming unit 1 is sent to the IOT main controller 71, and the IOT main controller 71, based on the position data of the color registration deviation detecting pattern 50 detected by the pattern detector 60.
A correction amount for correcting the formation position of each of the yellow (Y), magenta (M), cyan (C), and black (K) toner images formed by 3Y, 13M, 13C, and 13K is obtained.

In the IOT main controller 71,
Based on the position data of the color registration shift detection pattern 50, as shown in FIGS. 4 to 9, magnification shift in the main scanning direction, skew shift, sub-scan margin shift, main-scan margin shift, sub-scan periodic shift , The deviation amount of the main scanning periodic deviation is obtained, and the correction amount for correcting these deviation amounts is calculated.

Then, in the image output device 100 of the digital color printer, the magnification deviation in the main scanning direction, the skew deviation, the sub-scanning margin deviation, the main-scanning margin deviation, the sub-scanning cyclic deviation, which is obtained by the IOT main controller 71, The correction value for the periodical main scanning deviation is sent to the RAM 76 of the image processing apparatus 12.

The IOT main controller 71 performs a control operation of correcting the image positional deviation based on the image positional deviation correction value sent to the RAM 76 of the image processing apparatus 12.

Thereafter, the IOT main controller 7
As shown in step 106 of FIG. 21, the reference numeral 1 refers to the correction table as shown in FIG. 22B with the current temperature T as T0, and next executes the registration deviation correction operation based on the following equation. The upper limit value Tu and the lower limit value Tl of the temperature change are determined. Tu = T0 + ΔTn Tl = T0−ΔTm

Here, in the digital color printer, the upper limit value Tu and the lower limit value Tl of the temperature change at which the registration deviation correction operation is executed next are as shown in the temperature characteristic curve of the color registration deviation as shown in FIG. Information is obtained in advance and is determined according to the temperature characteristic curve of the color registration deviation.

FIG. 22B shows an example of a specific temperature parameter table corresponding to Δt in FIG. 22A. Although the usable temperature of the digital color printer is set to 10 ° C. or higher and lower than 45 ° C. here, it may be set to be usable in a temperature range other than this. Further, in FIG. 22B, the absolute temperature represents the detected value itself of the temperature inside the printer body 1 detected by the temperature sensor 75, and the numerical value of the absolute temperature in this table is equal to or higher than the temperature, It shows the temperature range below the temperature. For example, in FIG. 22B, the absolute temperature of 10 (° C.) is 10 ° C. or higher, 1
It means a temperature range of less than 5 ° C. In addition, the term “absolute temperature” does not indicate a physical absolute temperature, but an absolute temperature and a cabin temperature with respect to a relative temperature (a temperature difference between a certain temperature and a certain temperature). 1 at 10 ° C
This is because 0 ° C. and 20 ° C. mean a temperature of 20 ° C.

In this table, as shown in FIG. 22A, the absolute temperature in the printer body 1 is, for example, the temperature TA.
The maximum registration deviation amount of the main scanning magnification deviation when the temperature Δt1 (= TB-TA) changes from the temperature TB to the temperature TB is a parameter of the temperature change amount when the maximum registration deviation amount changes by a constant amount Δerror. Here, the maximum registration deviation amount of the main scanning magnification deviation will be described as an example of the color registration deviation amount on the vertical axis, but the present invention is not limited to this, and as described above, other misregistration deviation amounts of sub-scanning. : Lead deviation, skew deviation, BOW deviation, main scanning registration deviation amount: it may be set based on side registration deviation, lateral magnification deviation, partial magnification deviation, etc.

Further, the problem with the maximum registration deviation amount is that the absolute temperature in the printer body 1 is, for example,
Temperature Δt1 (= TB-T from temperature TA to temperature TB)
This is because even if the main-scanning magnification deviation occurs at the maximum when only A) changes, the registration deviation correction operation is executed at that time, and the registration deviation amount can be suppressed.

Further, the temperature change amount when the maximum registration shift amount changes by the constant amount Δerror is used as a parameter, for example, when the in-machine temperature changes by the temperature change amount, for example, the main scanning magnification shift Since there is a possibility that registration deviation will occur by the maximum registration deviation amount (allowable value) of
This is because if the registration shift correction operation is executed at this timing, the number of registration shift correction operations can be minimized.

Further, when the type of the deviation amount that causes the maximum registration deviation amount changes according to the absolute temperature, that is, when the machine temperature is between 10 ° C. and 20 ° C., the deviation amount of the main scanning magnification is the maximum. If the skew deviation amount in the main scanning direction is maximum when the in-machine temperature is between 20 ° C. and 30 ° C., the maximum registration deviation of the main scanning magnification is when the in-machine temperature is between 10 ° C. and 20 ° C. The temperature inside the machine is 2 when the amount changes by a certain amount Δerror1
Between 0 ° C. and 30 ° C., the temperature change amount when the maximum registration shift amount of the skew shift in the main scanning direction changes by a constant amount Δerror2 may be set as a parameter. That is, the type of registration deviation that determines the maximum deviation amount may be different depending on the range of the in-machine temperature.

More specifically, when the temperature at the first registration deviation correction operation is 26.0 ° C. in absolute temperature, the condition temperature at the next registration control operation is as shown in FIG.
With reference to, the following upper limit value Tu and lower limit value Tl are obtained. Tupper = 26.0 + 6.0 = 32.0 ° C. Tlower = 26.0−5.5 = 20.5 ° C.

Here, 6.0 ° C. or 5.5 ° C. in the formulas for calculating the upper limit value Tu and the lower limit value Tl are as shown in FIG.
In the table shown in Table 2, the upper limit (upper) parameter of the row of 25 ° C or higher and lower than 30 ° C is 6.0 ° C, and the lower limit (low) is
er) parameter at 5.5 ° C.

After executing the registration deviation correction operation (registration control operation) as described above, the IOT main controller 71, as shown in FIG. 21, based on the current temperature T, the condition temperature for the next registration deviation correction operation. The upper limit value Tu and the lower limit value Tl are determined (step 106), and it is determined whether or not the printer is powered off (step 107).
If the power of the printer has not been turned off, the process returns to step 102, and if the power of the printer has been turned off, the control operation ends.

Then, the IOT main controller 71
If the printer is not turned off, the process returns to step 102 to determine whether it is the registration control operation timing, and if it is the registration control operation timing, the in-machine temperature T
To confirm.

Next, the IOT main controller 71
It is determined whether the in-machine temperature T is equal to or higher than the upper limit value Tu or lower limit value Tl determined at the time of the previous registration control operation (step 104), and when the in-machine temperature T is not higher than the upper limit value Tu or lower than the lower limit value Tl. Returns to step 102, and when the in-machine temperature T is equal to or higher than the upper limit value Tu or equal to or lower than the lower limit value Tl, the registration deviation correction operation is executed (step 10
5).

In the first embodiment, the in-machine temperature T is checked and the registration deviation correction operation is executed on the basis of the flowchart shown in FIG. 21. At that time, in steps 102 to 104, the operation is always performed. , Internal temperature T
If the in-machine temperature T is equal to or higher than the upper limit value Tu or equal to or lower than the lower limit value Tl, the registration deviation correction operation is prioritized and the image forming operation is interrupted even during the image forming operation. Then, the registration shift correction operation may be executed.

As a result, during the series of image forming operations, the in-machine temperature T of the digital color printer becomes the upper limit value T.
It is possible to reliably prevent the occurrence of an unacceptable misregistration due to reaching u or more or the lower limit value Tl or less.

Further, when the internal temperature of the digital color printer rises and reaches the upper limit value Tu of 32.0 ° C., the IOT main controller 71 determines in step 104 of FIG. 21 that the internal temperature is equal to or higher than the upper limit value Tu. Then, the registration deviation correction operation is executed (step 105). After the registration shift correcting operation is executed, the newly calculated next registration control operation condition temperature is similarly as follows (step 106). Tupper = 32.0 + 6.5 = 38.5 ° C. Tlower = 32.0−6.0 = 26.0 ° C.

As described above, in the first embodiment, the temperature inside the printer body 1 is detected by the temperature sensor 75. However, when the temperature inside the printer body 1 changes by a certain temperature or more, the registration deviation correction operation is performed. Instead of running
According to the detected value of the temperature in the printer body 1 detected by the temperature sensor 75, a register as shown in FIG. 22B is referred to and a registration deviation correction operation start condition is determined at changing temperature intervals. The IOT main controller 71 is provided as a deviation correction operation determining unit.

Therefore, the detected value of the temperature inside the printer body 1 detected by the temperature sensor 75 (absolute temperature)
However, for example, when it is 26.0 ° C., the condition temperature at the time of the next registration control operation becomes the following upper limit value Tu and lower limit value Tl with reference to FIG. Tupper = 26.0 + 6.0 = 32.0 ° C. Tlower = 26.0−5.5 = 20.5 ° C.

That is, in the first embodiment, the temperature inside the printer body 1 is detected by the temperature sensor 75, and the detected in-machine temperature T is detected according to the detected in-machine temperature T.
Is 26.0 ° C., the upper limit value Tu is 32.0 ° C. and the lower limit value Tl is 20.5 as the condition temperature for the next registration control operation.
However, when the detected in-machine temperature is 24.0 ° C., the condition temperature for the next registration control operation is 29.5 ° C. for the upper limit value Tu and 19.5 ° C. for the lower limit value Tl. It is configured to determine the start condition of the registration deviation correction operation at changing temperature intervals.

Here, as shown in FIG. 22A, the temperature interval that changes according to the temperature T in the printer body 1 is the type of deviation that causes the maximum allowable misregistration amount in the color registration misregistration amount. Amount is a certain maximum allowable deviation Δer
Δt1, Δt2, depending on the temperature interval deviated by ror,
It is set to change such as Δt3 and Δt4.

That is, the temperature T in the printer body 1 is
Is low, the gradient of the color registration deviation amount due to the change of the in-machine temperature T is large. Therefore, when the temperature deviation Δt is relatively small, the registration deviation detection pattern 50 is changed.
Is formed, the registration deviation detection pattern 50 is detected, and the operation for correcting the registration deviation is executed. On the other hand, when the temperature T in the printer main body 1 is high, the gradient of the color registration deviation amount due to the change in the internal temperature T is small. Therefore, when the temperature interval Δt changes by a relatively large temperature, the registration deviation occurs. The detection pattern 50 is formed, the registration deviation detection pattern 50 is detected, and the operation for correcting the registration deviation is executed.

Therefore, as in the conventional case, the printer body 1
When the internal temperature T changes by a certain temperature, the registration deviation detection pattern 50 is formed, the registration deviation detection pattern 50 is detected, and the operation for correcting the registration deviation is executed. Corresponding to the low temperature range where the gradient of the color registration deviation amount due to
It is necessary to execute the registration deviation correction operation when the temperature changes by a small temperature.

Therefore, in accordance with the frequently performed registration deviation correction operation, the frequency of occurrence of so-called downtime in which the image forming operation is impossible, the toner consumption amount for registration registration patch formation, or the load on the cleaning member. In addition, there is a problem in that the waste toner recovery capacity and the like are unnecessarily increased.

On the other hand, in the case of the first embodiment of the present invention, when the temperature T in the printer body 1 is low, the gradient of the color registration deviation amount due to the change in the in-machine temperature is large, so that the relative When the temperature interval Δt changes by a small temperature, the registration deviation detection pattern 50 is formed, the registration deviation detection pattern 50 is detected, and the operation for correcting the registration deviation is executed. When the temperature T is high, the gradient of the color registration deviation amount due to the change in the in-machine temperature is small. Therefore, when the temperature interval Δt changes by a relatively large temperature, the registration deviation detection pattern 50 is formed. To detect the registration shift detection pattern 50,
It is only necessary to execute the operation for correcting the registration deviation, and the number of executions of the registration deviation correction operation can be reduced.

Therefore, in the case of the first embodiment of the present invention, it becomes possible to efficiently perform the registration deviation correction operation for correcting the color registration deviation caused by the temperature rise in the printer body 1, and the image forming operation. It is possible to reduce the so-called downtime, reduce the amount of toner consumed for forming the recon patch, reduce the load on the cleaning member, and reduce the waste toner recovery capacity.

Further, in the case of the first embodiment of the present invention,
If the downtime, the amount of toner consumed for forming the registration check patch, or the load on the cleaning member is the same as that of the conventional device, the number of registration deviation correction operations is increased to further improve the accuracy of the registration deviation correction operation. It becomes possible.

Second Embodiment In the second embodiment, the same parts as those in the first embodiment will be described with the same reference numerals. In the second embodiment, the registration deviation correction operation is started. It is configured to have at least one temperature interval table that stores the temperature interval that determines the value as a fixed value.

That is, in the above first embodiment, FIG.
As shown in (a) and (b), the color registration temperature characteristic curve information is stored in advance, and the in-machine temperature T0 during the initial registration control operation is set.
Is used as a reference, the process of setting the upper limit value Tu and the lower limit value Tl of the temperature interval for performing the subsequent registration deviation correction operation is
It is configured to be performed for each registration misalignment correction operation.

However, when a digital color printer or the like as a color image forming apparatus is assembled and then adjustments such as a registration deviation correction operation for shipping the apparatus are performed in a room where the temperature is constantly adjusted, The in-machine temperature T0 during the initial registration control operation can be set to a known constant value in advance. Therefore, in this case, the in-machine temperature T0 during the initial registration control operation is set to a fixed value, and the allowable color registration deviation amount Δerr is set.
or in consideration of temperature threshold values TA, TB, TC, TD, T
It is possible to set E to a fixed value, as shown in FIG.
It is not necessary to have the color registration temperature characteristic curve information as shown in (b), and in the situation where the printer is actually used, the temperature thresholds TA, TB for executing the next registration deviation correction operation,
TC, TD, and TE may be stored in the storage means as fixed values.

Therefore, in the second embodiment, the threshold value T of the temperature interval for determining whether to start the registration deviation correction operation.
A, TB, TC, TD, and TE are configured to have at least one temperature interval table stored as fixed values.

Further, referring to FIG. 22A, when the absolute temperature at the initial registration control is TA, T0 = T
A, the upper limit value Tu = TB, and the lower limit value Tl = TE can be set to fixed values. Then, when the in-machine temperature T of the printer body reaches TB, after performing the registration deviation correction operation, T0 = TB, the upper limit value Tu = TC, and the lower limit value Tl =
By setting TA, the registration control operation start condition temperature can be set in the same manner as above.

In this case, the in-machine temperature T at the time of executing the registration deviation correcting operation is TB, except during the initial registration control operation,
It is difficult to keep TC, TD, and TE at the same temperature. This is because there is no problem if the registration misregistration correction operation is immediately performed when the temperature condition is achieved, but there is a limitation on the timing at which the registration misregistration correction operation can be performed, and the temperature may deviate from the temperature shown above. Is. For this reason,
The execution temperature of the registration deviation correction operation is TB, T which is a fixed value.
There is a problem that it deviates from C, TD, and TE. In consideration of this error, TB, TC, except during the initial registration control operation,
TD and TE must be set. The temperature threshold value as described above is not fixed, and T is set for each registration deviation correction operation.
A process that can set the u / Tl value is more effective.

Furthermore, in order to further reduce the frequency of the registration deviation correction operation, the temperature information T0, Tu, and
It is also possible to configure to define the starting condition based on Tl.

The temperature information T0, Tu, Tl is stored in the RAM 76 or the like of the control unit for the normal misregistration correction operation. However, the information in the RAM 76 or the like is not stored due to the interruption of the power supply when the apparatus is turned off or the sleep mode is entered. Erased.
In that case, the information can be maintained regardless of whether the power supply is cut off, for example, the information may be stored in a memory such as the nonvolatile memory NVM or ROM.

Since the IOT main controller 71 can be maintained in the energized state even in the sleep mode, temperature information T0, Tu,
You may preserve Tl.

Therefore, the following cases can be considered as an embodiment to which the present invention is applied. (1) When the device power is turned on / return to sleep mode: Unconditional registration misalignment correction operation is performed. Timing other than the left: Registration misalignment correction operation is performed when the start condition is satisfied. (2) Device power ON: Unconditional registration misalignment correction. Operation execution Timings other than those on the left: Registration deviation correction operation is executed when the start condition is satisfied (3) All registration deviation correction operation timing: Registration deviation correction operation is executed when the start condition is satisfied

The registration misregistration correction operation timing described here is as follows: when the power of the apparatus is turned on, at the beginning of the print job, during the print job (a certain number of sheets, after a certain period of time, when the copy / print configuration has changed), after the print job is completed, and then the standby state. When, sleep mode transition, sleep mode return,
Just before power off.

The copy / print configuration change means a change such as an image size change, a resolution change, an image resolution change, or a process speed change corresponding to paper (thick paper, plain paper, OHP).

Further, when there are machine differences in the color registration temperature characteristics as shown in FIG. 22A, the color registration temperature characteristic tables are compared each time the registration deviation correction operation is performed, and the allowable amount as a result of the comparison is determined. If it exceeds, the table may be calibrated.

For example, a constant color registration deviation amount Δerr
When the registration deviation correction operation is performed under the temperature start condition set by predicting or as shown in FIG. 22B, the deviation amount actually detected by executing the registration deviation correction operation is the expected value Δerror. If it is larger or smaller than the above, the error in the color registration absolute temperature information (table / calculation general formula) due to machine difference can be reduced by changing (calibrating) the absolute temperature table or calculation general formula. Is.

The other structure and operation are the same as those in the first embodiment, and the description thereof will be omitted.

Third Embodiment FIGS. 24 and 25 show a third embodiment of the present invention. The same parts as those of the first embodiment will be designated by the same reference numerals and will be described below. In the third aspect, in accordance with the detected value of each temperature in the apparatus body detected by the temperature detecting means, it is determined whether the registration deviation correction operation is started when the temperature in the apparatus body changes. It is configured to have an arithmetic expression for obtaining the temperature interval.

That is, in the first embodiment,
As shown in FIG. 22A, a color registration characteristic curve showing how the color registration deviation amount changes with respect to the temperature (absolute temperature) in the printer body 1 is obtained in advance, and this color registration characteristic curve is obtained. On the basis of the above, according to the detected value of each temperature in the printer body 1 detected by the temperature sensor, it is determined how many times the temperature in the printer body 1 changes to start the registration deviation correction operation. The temperature interval to be set is configured so as to include a pre-stored start temperature interval table.

However, instead of the above-mentioned start temperature interval table, it is possible to provide an arithmetic expression for obtaining a temperature interval for determining whether to start the registration deviation correction operation.

Therefore, in the case of the third embodiment, a plurality of straight lines f (t), g (t), h (t) (or at least 1) are used as color registration characteristic curves shown by broken lines in FIG. Approximated with two quadratic curves)
It is stored in a RAM or the like and these approximate expressions (arithmetic expressions) f
From (t), g (t), and h (t), a specific deviation amount Δer
The upper and lower limits of temperature corresponding to ror are calculated each time.

For example, assuming that the temperature at the time of register shift correction operation (register control operation) is T0, this absolute temperature T0
Is the range of the arithmetic expression 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. Where the function f
(T) can be expressed as follows. Note that A and a indicate the slope and intercept of the function f (t) that represents the approximate straight line. f (t) = At + a (1)

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 ) Tonru.

Therefore, the temperature upper limit value Tupper and the lower limit value Tlower which determine the start condition of the next registration control operation are set.
Tupper = T0 + Δt = T0 + (1 / A) (Δerror-a) (4) Tlower = T0−Δt = T0− (1 / A) (Δerror-a) (5) Tlower may be expressed as follows.

As the arithmetic expressions stored in the RAM, NVRAM, etc., the following are approximate expressions: f (t) = At + a (1) g (t) = Bt + b (1) 'h (t) = Ct + c (1 ) ", The information of f (t), g (t), h (t) may be stored as it is, or the parameters A / a and B representing the approximate expression may be stored.
/ B, C / c may be stored as information.

Further, (1 / A) (Δerror-a),
(1 / B) (Δerror-b), (1 / C) (Δer
Ror-c) may be stored as information. Further, the effective temperature range of each approximate expression f (t), g (t), h (t) is also provided as information.

On the other hand, when the temperature range extends over a plurality of functions, the temperature may be calculated by an adjacent function for the error value deviated from the function, or the condition is bad, that is, the shift change amount per temperature is small. There is no problem even if the temperature condition is calculated with a larger function (in this case, the slope is larger).

In this case, for example, as shown in FIG.
If the temperature inside the machine when the registration control operation is performed is T0 and the temperature T0 is near below Tb (the switching temperature between the approximate expressions f (t) and g (t)), once f
It is sufficient to calculate Tu and Tl by the function of (t), calculate the temperature by the function of g (t) for the shift amount Δerror2 where Tu exceeds Tb, and obtain the upper limit value Tu ′.

However, a function with a large slope, in this case f
Even if the Tu calculated in (t) is used as the upper limit as it is, there is no problem because the allowable deviation amount is not exceeded. In this case, the calculation processing is reduced, but the number of operations of the register control is increased.

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, as in the second embodiment, the in-machine temperature during the initial registration control operation is performed. When T0 can be set to a known constant value in advance, the value of each temperature obtained by the approximate expression (1) or the like is calculated in advance based on the in-machine temperature T0 during the initial registration control operation. , May be stored in the storage means. However, in consideration of the case where the in-machine temperature T0 at the time of the initial registration control operation is different in a state where the printer is actually used, there is at least one temperature interval arithmetic expression that determines the temperature interval as a fixed value, and the in-machine temperature T0 is At the time of detection, a temperature interval for deciding 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.

The other structure and operation are the same as those in the first embodiment, and the description thereof will be omitted.

Embodiment 4 FIG. 26 shows a tandem type full color printer as an image forming apparatus according to Embodiment 4 of the present invention.

In FIG. 26, reference numeral 200 denotes a main body of a tandem type full color printer. Inside the main body 200 of the printer, yellow (Y), magenta (M), cyan (C) and black (K) are provided. Image forming units 201, 202, 203, 204 having photoconductor drums (image carrier) 211, 212, 213, 214 for
Charging roll (contact-type charging device) 2 for primary charging that contacts the photosensitive drums 211, 212, 213, and 214
21, 222, 223, and 224, and an image writing device 230 that irradiates yellow (Y), magenta (M), cyan (C), and black (K) laser beams 231, 232, 233, and 234. The photoconductor drums 211, 212, 21
Developing devices 241, 242, 24 for developing the electrostatic latent image formed on the image forming unit 3, 214 with toners of respective colors of yellow (Y), magenta (M), cyan (C), and black (K).
3, 244 and the four photoconductor drums 211, 21
Two of the photosensitive drums 211, 2, 213 and 214,
The first primary intermediate transfer drum (intermediate transfer member) 251 and the other two photoconductor drums 213 and 214 that come into contact with 212.
Second primary intermediate transfer drum (intermediate transfer member) 2 that contacts the
52 and the first and second primary intermediate transfer drums 251,
Secondary intermediate transfer drum (intermediate transfer member) 2 that contacts 252
53 and a final transfer roll (transfer member) 260 that comes into contact with the secondary intermediate transfer drum 253, a main part thereof is configured.

Photosensitive drums 211, 212, 213, 2
14 are arranged at regular intervals so as to have a common tangent plane. In addition, the first primary intermediate transfer drum 2
51 and the second primary intermediate transfer drum 252 are arranged such that their respective rotation axes are parallel to the photosensitive drums 211, 212, 213, and 214 and are in plane symmetry with a predetermined plane of symmetry as a boundary. ing. Further, the secondary intermediate transfer drum 253 includes the photosensitive drums 211, 212, 213,
214 and the rotation axis are arranged in parallel.

The photosensitive drums 211, 212, 21
Laser light 231, 232, and 23 corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) by the image writing device 230 is formed on the surface of the surface 3, 3, 214.
3, 234 are irradiated, and electrostatic latent images corresponding to the input image information for each color are formed. In addition, the photosensitive drum 21
The electrostatic latent images corresponding to the colors of yellow (Y), magenta (M), cyan (C), and black (K) formed on the surfaces of 1, 212, 213, and 214 are the developing devices 24 of the corresponding colors.
It is developed by 1, 242, 243, and 244, and visualized as a toner image of each color of yellow (Y), magenta (M), cyan (C), and black (K) on the photoconductor drums 211, 212, 213, and 214. It

Next, the above-mentioned photosensitive drums 211 and 21
The toner images of yellow (Y), magenta (M), cyan (C), and black (K) formed on Nos. 2, 213, and 214 are the first primary intermediate transfer drum 251 and the second primary intermediate, respectively. Secondary transfer is performed electrostatically on the transfer drum 252.
The yellow (Y) and magenta (M) color toner images formed on the photoconductor drums 211 and 212 are transferred onto the first primary intermediate transfer drum 251 onto the photoconductor drums 213 and 2, respectively.
The cyan (C) and black (K) color toner images formed on the image forming unit 14 are transferred onto the second primary intermediate transfer drum 252, respectively. Therefore, the first primary intermediate transfer drum 251
A monochromatic image transferred from either the photoconductor drum 211 or 212 and a dual color image in which two color toner images transferred from both the photoconductor drums 211 and 212 are superposed are formed on the upper side. become. Also, on the second primary intermediate transfer drum 252, the photosensitive drums 213 and 214 are also provided.
Form a similar monochromatic image and a dual color image.

The single-color or dual-color toner images thus formed on the first and second primary intermediate transfer drums 251 and 252 are electrostatically tertiary-transferred onto the secondary intermediate transfer drum 253. It Therefore, on the secondary intermediate transfer drum 253,
A final toner image from a monochromatic image to a quadruple color image of yellow (Y), magenta (M), cyan (C), and black (K) is formed.

Next, the final toner image from the monochromatic image to the quadruple color image formed on the secondary intermediate transfer drum 253 is tertiary-printed on the paper P passing through the paper transport path by the final transfer roll 260. Transcribed. The paper P passes through the paper transport path from the paper feed roll 290 and is fed to 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.

In this embodiment, the final transfer roll 26
0, the secondary intermediate transfer drum 253, or the like, on the image density detection medium, the color registration shift detection pattern 32 is shifted at the same position in the axial direction and in the process direction.
By forming 0 and 321, the color registration deviation detection patterns 320 and 3 of each color can be formed by one optical density detection unit.
21 can be detected. As the color registration shift detection patterns 320 and 321, for example, a pattern as shown in FIG. 27 is used.

In this embodiment, the color registration shift detection pattern 320 on the final transfer roll 260,
321 is transferred, and the optical density sensor 300 detects the densities of the color registration deviation detection patterns 320 and 321 transferred onto the final transfer roll 260.

The optical density sensor 300, as shown in FIG. 28, is provided at the central portion of the final transfer roll 260 in the axial direction.
It is arranged so as to be located on the extension line in the radial direction on the outer periphery of the final transfer roll 260. The optical density sensor 300 is mounted inside the holder 301 in a fixed state. A cleaning device 800 including a blade-shaped final cleaning member 801 is provided below the final transfer roll 260. In FIG. 28, 802 is a toner collection box, 803 is a support frame for the final transfer roll 260, 804 is a static eliminator provided on the support frame 803, and 805 is a bias plate.

The optical density sensor 300 shown in FIG.
As shown in FIG. 9, it is a specular reflection type sensor for detecting specular reflection light, and is composed of an LED or the like arranged at a predetermined incident angle φ with respect to the detection position on the surface of the final transfer roll 260. The light emitting element 302 and the light emitting element 30
In order to detect the specular reflected light that is irradiated from 2 to the detection position on the surface of the final transfer roll 260 and is specularly reflected from the detection position, the reflection angle equal to the predetermined incident angle is detected with respect to the detection position on the surface of the final transfer roll 260. Light receiving element 30 formed of a phototransistor or the like arranged at an angle
3 and 3.

The optical density sensor 300 detects the color registration deviation detection patterns 320 and 321 and corrects the color registration deviation at a predetermined timing.

The other structure and operation are the same as those in the first embodiment, and the description thereof will be omitted.

[0152]

As described above, according to the present invention, it is possible to efficiently perform the registration control operation for correcting the color registration deviation caused by the temperature rise in the apparatus main body, and thereby the image forming operation is performed. Color image formation that enables reduction of so-called downtime, reduction of toner consumption for forming registration control patch, reduction of load on cleaning member, and reduction of waste toner recovery capacity. A device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a tandem type digital color printer as a color image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a control circuit of a tandem printer as a color image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a tandem type digital color printer as a color image forming apparatus according to the first embodiment of the present invention.

FIG. 4A and FIG. 4B are explanatory diagrams showing magnification shifts in the main scanning direction.

5A and 5B are explanatory diagrams showing margin shifts in the main scanning direction, respectively.

FIGS. 6A and 6B are explanatory diagrams showing skew deviations.

FIG. 7A and FIG. 7B are explanatory diagrams respectively showing margin shifts in the sub-scanning direction.

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 a color registration shift due to various factors.

FIG. 11 is a configuration diagram showing an arrangement of a color registration shift detection pattern and a detection unit.

FIG. 12 is an explanatory diagram showing a color registration shift detection pattern.

FIG. 13 is an explanatory diagram showing a pattern for detecting color registration deviation.

FIG. 14 is a perspective configuration diagram showing a detection unit for a color registration shift detection pattern.

FIG. 15 is an explanatory diagram showing a method for detecting a pattern for detecting color registration deviation.

16 (a) to 16 (c) are explanatory views showing a main scanning coarse margin correction, a sub-scanning coarse margin correction, and a skew correction method, respectively.

17 (a) and 17 (b) are explanatory views respectively showing a main scanning fine margin correction, a sub-scanning fine margin correction, and a skew correction method.

18 (a) to 18 (c) are explanatory views showing methods of magnification balance deviation and magnification balance correction, respectively.

FIG. 19 is a waveform diagram showing each clock signal used for magnification balance correction.

FIG. 20 is an explanatory diagram showing a method for 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 the first embodiment of the present invention.

22A and 22B are a graph showing a color registration characteristic curve and a table showing a temperature range based on the graph.

FIG. 23 is a schematic configuration diagram showing another configuration example of a tandem type digital color printer as the color image forming apparatus according to the first embodiment of the present invention.

FIG. 24 is a graph showing a function approximating a color registration characteristic curve used for controlling the color image forming apparatus according to the third embodiment of the present invention.

FIG. 25 is a graph showing a function approximating a color registration characteristic curve used for controlling the color image forming apparatus according to the third embodiment of the present invention.

FIG. 26 is a schematic configuration 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 pattern for detecting color registration deviation.

FIG. 28 is a cross-sectional configuration diagram showing a sensor for detecting a color registration shift detection pattern.

FIG. 29 is an explanatory diagram showing a sensor for detecting a color registration shift detection pattern.

FIG. 30 is a block diagram showing a conventional color image forming apparatus.

FIG. 31 is a perspective configuration diagram showing a pattern used for registration deviation in a conventional color image forming apparatus.

[Explanation of symbols]

1: Printer body, 13K, 13Y, 13M, 13C:
Image forming unit, 14: ROS, 25: intermediate transfer belt, 50: pattern for detecting color registration deviation, 60: detection means, 71: IOT main controller (registration deviation correction operation determining means).

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DA09 DA13 EA18 EB04 EC03                       ED04 ED06 ZA07                 2H030 AA01 AB02 AD11 AD16 BB02                       BB22 BB42 BB43 BB56                 2H200 FA01 FA16 GA12 GA23 GA33                       GA44 GA47 GB12 GB25 GB41                       HA02 HA12 HA28 HB03 HB12                       HB22 HB26 JA02 JA30 JB10                       JC02 JC03 JC20 LA12 PA00                       PB16 PB27 PB39

Claims (7)

[Claims] 1. A plurality of image forming units for forming images of different colors are provided, and images of different colors formed by the plurality of image forming units are directly or through an intermediate transfer member on a recording medium. In a color image forming apparatus that forms a color image by transferring, the registration deviation detection pattern formed by each of the image forming units is transferred onto the same pattern detection member, and is transferred onto the pattern detection member. By the registration deviation correction operation executing means for detecting the transferred registration deviation detection pattern and executing the registration deviation correction operation, the temperature detecting means for detecting the temperature in the color image forming apparatus main body, and the temperature detecting means. The registration deviation correction operation determines the start condition of the registration deviation correction operation at a temperature interval that changes according to the detected temperature value in the apparatus main body. Color image forming apparatus characterized by comprising a constant section. 2. The color image forming apparatus according to claim 1, wherein the registration deviation correction operation determining unit corresponds to a detected value of each temperature in the apparatus main body detected by the temperature detecting unit, There is a temperature interval that determines how many times the temperature inside the apparatus body changes to start the registration shift correction operation, and the temperature interval depends on the detected value of the temperature inside the apparatus body. , A color image forming apparatus characterized by being set to different values. 3. The color image forming apparatus according to claim 2, wherein the temperature inside the apparatus main body is determined depending on the detected value of each temperature inside the apparatus main body detected by the temperature detecting means. A color image forming apparatus, comprising: a start temperature interval table that stores in advance a temperature interval that determines whether to start the registration shift correction operation when there is a change. 4. The color image forming apparatus according to claim 2, wherein the temperature inside the apparatus main body is determined according to the detected value of each temperature inside the apparatus main body detected by the temperature detecting means. A color image forming apparatus comprising an arithmetic expression for obtaining a temperature interval for deciding whether or not to start the registration shift correction operation when there is a change. 5. The color image forming apparatus according to claim 1, wherein an upper limit value and a lower limit value of a temperature interval for executing the next registration deviation correction operation each time the registration deviation correction operation is executed. And a color image forming apparatus. 6. The color image forming apparatus according to claim 2, further comprising at least one temperature interval table in which a temperature interval for determining whether to start the registration shift correction operation is stored as a fixed value. Characteristic color image forming apparatus. 7. The color image forming apparatus according to claim 2, further comprising at least one temperature interval calculation formula that determines a fixed value as a temperature interval that determines whether to start the registration shift correction operation. And a color image forming apparatus.