JPH11190920A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove or reduce-irregular noise element from signals transmitted as a result of reading image data used for controlling conditions under which images are formed on a recording member, and to obtain correct dot size and line width. SOLUTION: On a transfer carrying belt 216 for carrying recording paper on which an image is recorded by an electrophotographic system, an image pattern 10 consisting of a cyclical repetition of toner image 12 and blank space 14 is formed and consecutively read by a reading means 230. The image pattern 10 is irradiated with a semiconductor laser 231, and light reflected from it is received by a photodiode 236. The detection output of the photodiode 236 is divided into areas. By dividing it into the areas corresponding to the cycle of the repetition in the image pattern and by performing an addition processing for each area, irregular noise element can be removed or reduced, and a correct line width can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic digital copying machine or a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, image forming apparatuses such as digital copying machines and laser beam printers utilizing an electrophotographic system have been widely used. In such an image forming apparatus, an electrostatic latent image is formed by a laser beam on a photosensitive member serving as an image carrier, developed by toner, and a toner image is directly or indirectly formed on a recording member such as recording paper. An image is formed by transfer. An image is formed by two-dimensionally arranging minute pixels, and a method of changing the size of a basic pixel is used to obtain gradation of the image. Particularly when a color image is formed, usually, yellow (Y), magenta (M),
When combining the four color toners of cyan (C) and black (B), display of various types of colors is realized based on the difference in the gradation of the toner image of each color superimposed as an individual pixel.

In an electrophotographic image forming apparatus, the characteristics of a photoreceptor or the like change due to environmental factors such as temperature and humidity, and the size of a formed pixel changes even when image forming conditions are kept constant. And it is difficult to obtain stable gradation. Further, the characteristics of the photoreceptor and the like may change over time. Various correction methods have been proposed to prevent image quality deterioration due to changes in environmental factors such as temperature and humidity and aging.

For example, in the prior art disclosed in Japanese Patent Application Laid-Open No. 63-280275, a toner image is formed under predetermined conditions on a photoreceptor or a transfer member arranged in contact with the photoreceptor, and a toner is formed by a sensor. There has been proposed a method of determining a control parameter for image formation by reading a dot size and a line width of an image.

[0005]

However, when a toner image is read by a sensor as in the prior art of Japanese Patent Application Laid-Open No. 63-280275, a noise component due to deterioration of a photosensitive member or a transfer member is included in a read signal by the sensor. And
Electrical noise components from the periphery of the sensor are irregularly included. The noise component may appear at a level equal to or higher than that of the portion having the toner image even in the portion having no toner image. In such a case, it may not be possible to read an accurate dot size or line width of the toner image. If an accurate dot size and line width of a toner image cannot be read, it is not possible to accurately correct environmental changes and aging changes, which in turn causes image quality degradation.

An object of the present invention is to remove or reduce irregular noise components from a read signal of image data for controlling conditions for forming an image on a recording member, and obtain an accurate dot size and line width. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0007]

According to the present invention, there is provided an image forming apparatus for forming a recorded image on an image carrier and transferring the image onto a recording member, wherein a detected pattern having a predetermined shape is formed on the image carrier. A pattern forming means for forming a continuous image pattern, a pattern reading means for continuously reading an image pattern formed by the pattern forming means, and a detection signal continuously read by the pattern reading means in a predetermined area. Calculating a shape of a detected pattern of the image pattern based on a processing result of the addition processing means; an adding processing means for adding detection signals of the areas divided by the area dividing means; ,
An image forming apparatus comprising: a control unit configured to control a condition for forming the recorded image based on a result obtained by comparing a calculation result with the predetermined shape.

According to the present invention, the image pattern formed by the pattern forming means is continuously read by the pattern reading means. The area dividing means divides the detection signal from the pattern reading means into a predetermined area. The addition processing means performs an addition process on the detection signals of the divided areas. The control means calculates the shape of the detected pattern of the image pattern based on the result of the addition processing, and controls the conditions for forming the recorded image based on the result of comparing the calculation result with the predetermined shape. By dividing a continuous detection signal from the pattern reading means and adding the divided signals, a noise component included in the detection signal can be reduced, and the shape of the detected pattern of the image pattern can be accurately calculated. Can be. By forming the pattern to be detected so that the line width and dot size can be detected, it is possible to accurately control the line width and dot size necessary for improving image quality, and to achieve stable gradation. Obtainable.

Further, in the present invention, the pattern forming means forms the image pattern so that a plurality of predetermined unit pattern images are continuously formed at predetermined intervals, and the area dividing means is such that the pattern reading means It is characterized in that area division is performed according to a detection signal continuously read from an image pattern.

According to the present invention, a plurality of predetermined unit patterns are continuously formed at predetermined intervals by the pattern forming means, and a pattern to be detected can be formed periodically.
Since the area dividing means divides the area in accordance with the detection signal continuously read by the pattern reading means, the area can be divided in accordance with the pattern to be detected which is periodically repeated, and the noise component can be obtained by utilizing the periodicity. Can be reduced.

Further, in the area dividing means of the present invention, an area width to be divided is determined according to a predetermined shape of a detected pattern of the image pattern.

According to the present invention, the region width of the detection signal divided by the region dividing means is made to correspond to the predetermined shape of the detected pattern, so that the position of the detected pattern with respect to the divided region can be kept constant. In addition, it is possible to accurately detect a line width and a dot size necessary for improving image quality.

In the present invention, the recorded image is a color image formed by superimposing images of respective colors formed in accordance with a plurality of pieces of color-separated image information, and the pattern forming means converts the image pattern into a pattern of each color. Are formed so as to be continuous according to a predetermined condition, and the control means calculates the shape of the detected pattern from the image pattern of each color,
Controlling the conditions for recording image formation based on the calculation results,
It is characterized in that it is performed for each color.

According to the present invention, an image pattern formed by the pattern forming means so that a pattern of each color formed according to a plurality of color-separated image information is continuous according to a predetermined condition is continuously read by the pattern reading means. Read. Since the control means controls the conditions for forming a recorded image based on the shape of the detected means of the image pattern of each color for each color, a color image with excellent image quality can be formed.

Further, according to the present invention, a color recording image is formed on an image carrier provided for each predetermined image color to be separated, and the recording images formed for each image color are superimposed on a recording member. A pattern forming means for forming a continuous image pattern including a detected pattern having a predetermined shape on an image carrier for each image color, and an image carrier for each image color. Pattern reading means provided for each image and continuously reading an image pattern formed by the pattern forming means; and area division for dividing a detection signal continuously read by the pattern reading means into a predetermined area for each image color. Means, addition processing means for adding the detection signals of the areas divided by the area division means for each image color, and image processing based on the processing results of the addition processing means for each image color. Control means for calculating the shape of the pattern to be detected of the turn, and controlling the conditions for forming the recorded image for each image color based on a result of comparing the calculation result with the predetermined shape. Image forming apparatus.

According to the present invention, an image pattern including a pattern to be detected having a predetermined shape is formed on the image carrier for forming an image for each predetermined image color to be separated. . The detection signal continuously read for each image color by the pattern reading means is divided into predetermined areas by the area dividing means. The addition processing means adds the detection signals of each area, and the control means calculates the shape of the detected pattern of the image pattern based on the processing result for each image color, and compares the calculation result with the predetermined shape. Based on the result, the conditions for forming the recorded image are controlled for each image color. Since the conditions for forming an image on the image carrier corresponding to each image color can be accurately controlled based on the formation and detection of the image pattern, the line width and dot size required for image quality improvement For example, accurate control can be easily performed for each image color, and stable gradation can be obtained.

[0017]

FIG. 1 shows a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention. In the image forming apparatus 1, a process of creating image data representing an image to be formed by the image forming unit 2 is performed, and a control parameter for recording the image data is corrected by the control parameter correcting unit 3. The line width control operation based on the correction of the control parameters is performed when the power of the image forming layer value 1 is turned on or when the operation is resumed after being left for a certain period of time. The control parameter correction means 3 includes an area dividing means 4, an addition processing means 5, a control means 6, and an addition memory 7 realized by a program operation of a computer device. The area dividing means 4 performs a predetermined process on the detection signal of the image pattern 10 continuously read by the pattern reading means 8 at a constant time interval, and divides the detection signal into a plurality of time-divided areas. The addition processing means 5
The addition processing of the detection signal is performed using the addition memory 7 for each area divided by the area dividing means 4. The control unit 6 detects a predetermined detection target pattern included in the image pattern 10 such as a dot size and a line width based on the addition processing result, and corrects a control parameter based on the detection result.

FIG. 2 shows an example of the configuration of the image pattern 10. The image pattern 10 is formed by periodically repeating a linear toner image 12 and a blank 14 extending in the main scanning direction. The width of the toner image 12 in the sub-scanning direction perpendicular to the main scanning direction is equivalent to two dots in pixel units.
Is 22 dots in the sub-scanning direction. That is, in the image pattern 10, a linear toner image 12, which is a pattern to be detected, is repeated continuously at a constant cycle.

An image pattern 10 as shown in FIG. 2 is formed on the conveyor belt 16 shown in FIG. The transport belt 16 is originally provided for transporting the recording paper 18 in the transport direction 17. The transport direction 17 coincides with the sub-scanning direction, and a toner image 20 formed corresponding to image data from the image forming unit 2 is transferred onto the recording paper 18. The toner image 20 is obtained by an electrophotographic method in which an electrostatic latent image is formed on the surface of the photosensitive drum 22 according to image data, and is developed with toner. The formation of the electrostatic latent image and the supply of the toner for development are performed by the developing device 24 including the photosensitive drum 22. The image pattern 10 for control parameter correction is formed directly on the transport belt 16 by the developing device 24.

In a normal copying operation, the image forming apparatus 1 such as a digital color copying machine transfers the developed toner image 20 from the developing device 24 to the recording paper 18 on the transport belt 16. The image forming means 2, which is also a pattern forming means, controls the control parameter correcting means 3 and the developing device 2 so as to correct the control parameters when, for example, a power switch is turned on.
4, the image pattern 10 is written on the photosensitive drum 22 of the developing device 24 and developed, and
The image data is transferred directly to the upper side and read by the pattern reading means 7. The reading start timing is synchronized with the writing start timing of the image pattern 20 in the developing device 24. When a predetermined time elapses after the start of writing, an interrupt signal is generated for the CPU constituting the control parameter correction means 3, and reading is started.

The reading interval by the pattern reading means 8 is
It is set so that reading can be performed 36 times in one dot when the resolution is 600 dpi. Transport direction 17
The conveyance speed of the conveyance belt 16 is set at 117 mm / sec. Since the resolution is 600 dpi, 1
The time required for the dot size toner image to pass through the reading position of the pattern reading means 8 is about 360 μsec. Therefore, temporally, reading is performed once every 10 μsec. Such a reading time interval is merely an example, and the reading interval is not limited to this.

FIG. 3 shows an image pattern 1 as shown in FIG.
An example of an output value of the pattern reading unit 8 is shown as data obtained by reading 0 and measuring the line width of the toner image 12. The output value is divided by the region dividing means 4 into a predetermined region having a period T. The addition processing means 5 writes the output values from the pattern reading means 8 into the addition memory 7 sequentially from the first divided area and adds them. In the addition memory 7, 0 is always input as an initial state before the start of reading.
The division cycle of the area is equal to the writing cycle of the toner image 20 in the developing device 24, and the division point can be set at an arbitrary position. One region always contains a detection signal of one or less toner image.

After all the detected output values of the first area are written to the addition memory 7 and added, the detected output values of the next area are first written to the addition memory 7 and added to the added value. The writing to the addition memory 7 is repeated a predetermined number of times.
The control means 6 extracts the maximum value Max and the minimum value Min from the calculated values subjected to the addition processing, averages the two extracted values, and sets the obtained average value AVE as a threshold value for addition. The calculated value stored in the memory 7 is binarized. In each area of the period T, the toner image 12 of the image pattern 10
In addition, regular changes in output values corresponding to the blanks 14 and irregular changes due to noise are mixed. By repeating the addition process, irregular noise components are canceled out,
The stack of regular changes corresponding to the image pattern 10 is emphasized.

FIG. 4 shows the result of performing an addition process on the detection signal indicating the output value shown in FIG. When the output value equal to or larger than the threshold value AVE is binarized by setting it to “1” and the output value smaller than the threshold value AVE to “0”, the portion corresponding to the toner image 12 of the image pattern 10 becomes “1”, and the noise component corresponding to the blank 14 is It turns out that it becomes "0". The line width W of the image pattern can be converted into time corresponding to the number of output value samples. Further, the time can be converted into an actual line width of the toner image 12 based on the transport speed of the transport belt 16. Image pattern 10 obtained as shown in FIG.
Is compared with a predetermined line width reference value. The line width reference value is equal to the ideal width of the toner image 12 and is 600 dpi.
In the case of the toner image 12 having a resolution of 2 dots and a width of 2 dots, the line width reference value is 84.7 μm.

The control means 6 in FIG. 1 determines a control parameter for image formation from the result of comparison between the calculated value of the line width W by the addition processing and the line width reference value. The determined control parameters are fed back to the image forming means 2, and the line width is controlled by reflecting the control parameters when the image pattern 10 is formed. For example, if the line width W calculated by the addition process is 10 μm thicker than a predetermined line width reference value, the control parameters
Toner image 1 in image pattern 10 formed by
This is a value necessary to change the developing bias voltage applied in the developing device 24 by a corresponding value so that 2 becomes thinner by 10 μm. The developing bias voltage to be changed is a value determined by the temperature and humidity during use and the number of printed sheets. The image forming unit 2 to which the control parameters are fed back changes the developing bias voltage according to the control parameters so that the line width of the toner image 12 becomes substantially equal to the line width reference value.

FIG. 5 shows a schematic electrical configuration of a digital color copying machine as the image forming means 2 in the embodiment of FIG. The image forming unit 39 includes an image data input unit 40, an image processing unit 41, an image data output unit 42, a hard disk 4
3. Central processing unit (hereinafter abbreviated as "CPU") 44;
An operation board unit 45 and a recording mode selection switch 46 are included. The image data is not only reproduced and recorded from the image data output unit 42, but also transmitted from the Personal Digital Assistants to the P via the image data communication unit 47.
Image data can be communicated between a portable information communication device abbreviated as DA, a personal computer abbreviated as a PC, and a facsimile apparatus abbreviated as a facsimile. The image forming section 39 also includes a main memory 48 that is also used for storing image data.

The CPU 44 includes a scanner-related control unit 51 and a printer-related control unit 5 including a color CCD 40a for operating as a digital color copying machine.
2. It also controls an automatic document feeder (hereinafter abbreviated as "ADF") related load 53 and a desk related load 54. The scanner related load 51 includes a motor and a solenoid for reading a document. Reference numeral 52 denotes a motor, a solenoid, a high voltage, and the like for forming a toner image on recording paper by an electrophotographic method and transporting the recording paper, and an ADF-related load 53 for automatically transporting a document. The desk-related load 54 includes a motor, a clutch or a sorter for classifying and storing the copied recording paper. Image data read by the color CCD 40a included in the scanner is electrically input.
A normal recording / reproducing mode and a ticket issuing mode can be selected.

FIG. 6 shows a configuration related to the image data input section 40 and the image processing section 41 in FIG. 5 in more detail. The color CCD 40a includes three lines of CCDs,
The color original image is read in three colors of RGB, and line data of each color is output. Image data input unit 4 for processing line data read by color CCD 40a
0, the shading correction circuit 40b, the line matching unit 40c, the sensor color correction unit 40d, and the MTF correction unit 40
e, a gamma correction unit 40f and a compression processing unit 40g. The shading correction circuit 40b includes a color CCD 4
0a corrects the line image level of the read line data. The line matching unit 40c has a line buffer or the like in order to correct a time shift between the three color image line data. The sensor color correction unit 40d corrects the color data of the three line data output from the color CCD 40a. The MTF correction unit 40e corrects the change of the signal of each pixel so as to give a sharp edge. The gamma correction unit 40f corrects the lightness and darkness of the image to perform visibility correction. The compression processing unit 40g compresses the digital line data for three lines and reduces the required number of bits. Image data output from the compression processing unit 40g is represented by a Lab 'signal.

The image processing section 41 includes a color space correction circuit 41
a, masking circuit 41b, black detection circuit 41c, under color removal / black point (hereinafter abbreviated as "UCR BP") circuit 4
1d, a density processing circuit 41e, a scaling processing circuit 41f, a separation / screen circuit 41g, and a compression processing section 41h. The color space correction circuit 41a corrects the color gamut of a color image signal input via the image data input unit 40 or the image data communication unit 47 to the color gamut of the color toner provided in the digital color copying machine. The masking circuit 41b converts the Lab 'signal of the input image data into a YMC signal representing yellow, magenta, and cyan corresponding to each recording unit as a digital color copying machine. The black detection circuit 41c detects a black component K from the Lab 'signal of the color image. UCR / BP circuit 41d
Performs black addition processing of adding the black component K signal output from the black detection circuit 41c to the YMC signal output from the masking circuit 41b. The density processing circuit 41e adjusts the density of the color image signal based on the density conversion table. The magnification processing circuit 41f performs magnification conversion of the input image information based on the set magnification. The separation / screen circuit 41g detects a character / photo / halftone area in the image information from the input image data and separates the area, and determines an output pattern of the image. The compression processing unit 41h
Compress digital data represented by each component of MCK,
Reduce the number of required bits. Image data output unit 4
Reference numeral 2 denotes a laser scanner unit (hereinafter, referred to as “LS”) that performs laser recording for forming an image by electrophotography for each color.
U "), 42a-42d, and each LSU 42a-
A laser control unit (hereinafter referred to as “L”) that performs pulse width modulation on the output of 42d based on the image data of each color.
SU CONT ”) 42x).

The hard disk 43 sequentially receives image data of a total of 32 bits of 8 colors for each of the four colors of YMCK serially output from the image processing unit 41, and stores and manages each of the four hard disks 43a, 43b, 4
3c and 43d, and sequentially receives 32-bit image data output from the image processing unit 41, converts the 32-bit data into 8-bit 4-color image data while temporarily storing them in a buffer, and converts the data into four hard disk 43a. , 43b, 43
a hard disk control unit (hereinafter, abbreviated as “HD CONT”) 43 for dividing and managing the hard disks 43 and 43d
x.

The CPU 44 includes an image data input unit 40, an image processing unit 41, an image data output unit 42, a hard disk 43, an image data communication unit 47, and the like.
Control based on a predetermined sequence. BUS6
0, the image data input unit 40 and the image processing unit 41
Alternatively, an image editing unit 70 is also connected to perform predetermined image editing on image data stored in the hard disk 43 or the main memory 48 after passing through the image data communication unit 47.

The image data communication unit 47 is a communication interface for receiving image data from an external image input processing device provided separately from the digital color copier, and is an infrared interface (hereinafter referred to as "IR I / I").
F) 47a, a scanner interface (hereinafter abbreviated as “Scanner I / F”) 47b, a video interface (hereinafter abbreviated as “Video I / F”) 47c, a facsimile interface (hereinafter “Fax I”). / F ") 47d and RIP /
NW I / F 47e and the like. IR I / F47a
Can perform infrared communication with a PDA or the like. Sc
The Anna I / F 47b can be connected to a PC based on the SCSI standard or the like. Video I / F
47c can be connected to CS. Fax I /
F47d can be connected to a facsimile machine via a public telephone line. RIP / NW I / F47e
Can be connected to a personal computer (PC), a network (NW), a portable information communication device (PDA), or the like. The image data input through such an image data communication unit 47 is also input to the image processing unit 41 and, if color space correction or the like is performed, a data level that can be handled by the image recording unit of the digital color copying machine. Are converted to the hard disks 43a to 43d
Will be stored and managed.

Referring to FIG. 5, an operation board unit 45 including an operation panel and the like is connected to CPU 44 so as to be able to communicate with each other, and controls signals according to a copy mode set and input by an operator. The data is transferred to the CPU 44 so that the operation mode of the digital color copying machine can be switched. Further, a control signal indicating the operation state of the digital color copying machine is transferred from the CPU 44 to the operation board unit 45. On the operation board unit 45 side, based on the control signal, what kind of apparatus as the digital color copying machine is currently used. The operating state is displayed on a display unit or the like so as to indicate to the operator whether the operating state is in the normal state.

FIG. 7 shows an operation panel 80 related to the operation board unit 45 of FIG. A liquid crystal display device 81 of a touch panel type is arranged at the center of the operation panel 80, and various mode setting keys are arranged around it. On the screen of the touch panel type liquid crystal display device 81, a screen switching area for constantly switching to a screen for selecting an image editing function is provided, and by directly pressing this area with a finger, various image editing functions can be selected. A list of various editing functions is displayed on the screen of the liquid crystal display device 81. The editing function is set by directly touching the region where the desired function is displayed with the finger from the various editing functions displayed in this manner.

Hereinafter, a group of various setting keys arranged on the operation panel 80 will be briefly described. The dial 82
It is provided for adjusting the brightness of the screen of the liquid crystal display device 81. The automatic magnification setting key 83 is set to a mode in which a copy magnification is automatically selected when operated. The zoom key 84 is used to set the copy magnification in steps of 1%. Fixed magnification keys 85 and 86 are provided for reading and selecting a fixed magnification. The same-magnification key 87 is provided for returning the copying magnification to the standard magnification, ie, the same magnification. The density switching key 88 is provided to switch the density adjustment from automatic to manual or to the photograph mode. Density adjustment key 89
Is provided to finely set the density level in the manual mode or the photograph mode. Tray selection key 90
Is provided to select a desired paper size from paper sizes set in a paper feeding unit of the copying machine.
The copy number setting key 91 is provided for setting the number of copies. The clear key 92 is used to clear the number of copies,
Operate when copying is stopped in the middle of continuous copy mode operation. A start key 93 is provided to instruct the start of a copying operation. The all release key 94 is provided to release all of the currently set modes and return to the standard state. When the interrupt key 95 is operated to copy another original during the continuous copying operation, the continuous copying operation is temporarily stopped, and when the copying of another original is completed, the original continuous copying operation is returned again.

The operation guide key 96 is provided to operate the copier when the user does not know the operation of the copier and to display a message on the operation method of the copier using the liquid crystal display device 81. When the message forward key 97 is operated, the continuation of the message displayed by operating the operation guide key 96 is displayed. The screen mode setting key 98 is used to set a duplex copying mode. The post-processing mode setting key 99 is used to set an operation mode of the post-processing device for sorting the copy discharged from the copying machine. The memory transmission mode key 100 is used to temporarily store image data obtained by reading a transmission original document in the main memory 48 or the hard disk 4.
3 to transmit the image data after storing it in the image memory. An operation mode switching key 101 is used to switch the operation mode of the digital color copying machine between copy, facsimile, and printer. The one-touch dial key 102, when used as a facsimile machine, stores a telephone number of a destination in advance, and is used to connect to the destination via a public telephone network by one-touch operation at the time of transmission.

In the present embodiment, the operation panel 80 is also provided with the recording mode selection switch 46. The operation panel 80 and various keys arranged thereon as shown in FIG. 7 are merely examples, and differ according to various functions mounted on an image forming apparatus such as a color digital copying machine. That is natural.

FIG. 8 schematically shows the mechanical structure of the digital color copying machine of the present embodiment. On the upper surface of the copying machine main body 109, a document table 111 of the image reading unit 110 and an operation panel 80 are provided. On the upper surface of the platen 111,
An ADF device 112 that can be opened and closed is attached to the document table 111. The ADF device 112 supports the double-sided document, and conveys the document such that one surface of the document is opposed to a predetermined position of the document table 111. After reading the image on one surface, the other surface of the document is changed to the document table. The document is inverted and conveyed so as to face a predetermined position 111. When the reading of both sides of one original is completed, the original is discharged, and a double-sided conveying operation is performed for the next original. The operation of transporting the document and reversing the original is controlled in relation to the operation of the entire copy. When the ADF device 112 is not used, the original is placed directly on the original platen 111 to perform copying.

In order to read an image of a document on the document table 111, a document scanning body which reciprocates in parallel along the lower surface of the document table 111 is arranged below the document table 111.
The document scanning body includes a first scanning unit 113, a second scanning unit 114, an optical lens 115, and a color CCD 40a as a photoelectric conversion element. The first scanning unit 113 reciprocates in parallel at a predetermined scanning speed while maintaining a constant distance from the lower surface of the document table 111, and an exposure lamp for exposing the document image surface and a light reflected from the document for a predetermined time. And a first mirror for deflecting in the direction of. The second scanning unit 114 includes second and third mirrors for further deflecting the reflected light image from the document deflected by the first mirror in a predetermined direction.
Reciprocate in parallel with the scanning unit 113 having a constant speed relationship. The optical lens 115 reduces the reflected light image from the document deflected by the third mirror and forms an image at a predetermined position as an optical image. The color CCD 40a sequentially photoelectrically converts the light image formed by the optical lens 115, converts the reflected light image from the document into an electric signal, and outputs the electric signal.

An image forming section 210 is arranged below the copying machine body 109. On the lower side of the image forming unit 210,
A paper feed mechanism 211 is provided, and the recording papers 18 are stored in a stacked state in a paper tray 211a. The transport timing of the recording paper 18 that is separated and supplied one by one is controlled by a pair of registration rollers 212 disposed in front of the image forming unit 210, and is supplied and transported so as to match the timing with the image forming unit 210. A transfer conveyance belt mechanism 213 is disposed below the image forming unit 210, and a transfer conveyance belt 216 corresponding to the conveyance belt 16 in FIG. 1 is stretched between a plurality of rollers such as a driving roller 214 and a driven roller 215. Is done. The transfer conveyance belt 216 electrostatically attracts the recording paper 18 and conveys the recording paper 18 in a substantially horizontal direction. A fixing device 217 for fixing a toner image transferred and formed on the recording paper 18 is disposed downstream of the transfer conveyance belt mechanism 213. The recording paper 18 that has passed between the fixing roller nips of the fixing device 217 passes through a conveyance direction switching gate 218,
The paper is discharged by a discharge roller 219 onto a discharge tray 220 attached to the outer wall of the copying machine body 109.

The conveyance direction switching gate 218 is used to select whether to discharge the recording paper 18 after fixing outside the copying machine main body 109 or to resupply the recording paper 18 to the image forming unit 210 again.
The conveyance path of the recording paper 18 is switched. The recording paper 18 whose conveyance direction is switched again toward the image forming unit 210 by the conveyance direction switching gate 218 is turned over by the switchback conveyance path 221 and then turned over.
Is supplied again. On the upper side of the transfer conveyance belt 216 stretched substantially in parallel by the driving roller 214 and the driven roller 215, etc., the first, second, and third are arranged in order from the upstream of the conveyance path in the vicinity of the transfer conveyance belt 216. And a fourth image forming station Pa, Pb, Pc, Pd. The transfer conveyance belt 216 is frictionally driven by a drive roller 214 in a direction indicated by an arrow Z, and the recording paper 1 as a transfer material fed through a paper feeding mechanism 211.
8 and the image forming stations Pa, Pb, Pc,
Conveyed sequentially to Pd.

Each image station Pa, Pb, Pc, P
d has substantially the same configuration, and is a photosensitive drum 222a, 222b, 222c, which is rotationally driven in the direction of arrow F.
222d. Each photosensitive drum 222a, 2
Chargers 223a, 223b, 223c, 223d for uniformly charging the photosensitive drums 222a, 222b, 222c, 222d are provided around the periphery of 22b, 222c, 222d.
And the photosensitive drums 222a, 222b, 222c, 22
Developing device 224 for developing an electrostatic latent image formed on 2d
a, 224b, 224c, 224d, transfer dischargers 225a, 225b, 225c, 225d for transferring the developed toner image onto the recording paper 18, which is a transfer material, and on the photosensitive drums 223a, 223b, 223c, 223d. Cleaning means 226a, 226 for removing toner remaining on
26b, 226c, and 226d are sequentially arranged along the rotation direction F. Each photosensitive drum 222a, 222
Above b, 222c and 222d, a semiconductor laser device for generating dot light modulated in accordance with image data, a deflecting device for deflecting light from the semiconductor laser device in the scanning direction, and a deflecting device. LSUs 42a, 42b, 42c, 42d each comprising an fθ lens or the like for forming the laser beam on the surface of the photosensitive drums 222a, 222b, 222c, 222d are provided.

The LSUs 42a, 42b, 42c and 42d receive pixel signals corresponding to a yellow component image, a magenta component image, a cyan component image and a black component of a color deflection image, respectively. Image stations Pa, P
b, Pc, Pd photosensitive drums 222a, 222b, 2
An electrostatic latent image corresponding to the color-converted document image is formed on 22c and 222d. Developing devices 224a, 224
b, 224c, 224d have yellow, magenta,
Since cyan and black toners are stored, when the electrostatic latent image is developed with the toner, the color-converted document image information is reproduced as a toner image of each color.

The driving roller 214 is driven to rotate by a motor 227. Between the first image forming station Pa and the paper feed mechanism 211, a suction charger 228 having a brush for the recording paper 18 is provided. Suction charger 22
Reference numeral 8 denotes a state between the first image forming station Pa and the fourth image forming station Pd in a state where the surface of the transfer conveyance belt 216 is charged and the recording paper 18 supplied from the paper feeding mechanism 211 is securely attracted. To be transported without displacement. Fourth image forming station Pd and fixing device 21
, A charge eliminator (not shown) is provided almost directly above the drive roller 214.
An AC electric field is applied to separate the recording paper 18 electrostatically attracted onto the recording paper 6.

In the above-described digital color copier, the recording paper 18 as a recording member is in the form of a cut sheet. The recording paper 18 is sent out from the paper tray 211a and is fed into the guide of the paper feed path of the paper feed mechanism 211. When supplied,
The leading end of the recording paper 18 is detected by a sensor not shown. In accordance with the detection signal output from the sensor, the sheet is temporarily stopped by the pair of registration rollers 212, and the transfer conveyance belt rotating in the arrow Z direction at the same timing as the operation of each image forming station Pa, Pb, Pc, Pd. 216. Since the transfer / conveying belt 216 is charged at a predetermined level by the above-mentioned charging device 228 for adsorption, the recording paper 18 is stably conveyed and supplied while passing through the image forming stations Pa, Pb, Pc and Pd. You. Each image forming station Pa, Pb, P
In c and Pd, toner images of each color are formed, and are superimposed on the surface of the recording paper 18 which is being electrostatically attracted and conveyed by the transfer / conveyance belt 216. When the transfer of the image by the fourth image forming station Pd is completed, the charge is removed from the leading end of the recording paper 18 and the transfer conveyance belt 216 is removed.
It is peeled off from above and guided to the fixing device 217. Finally, the recording paper 18 on which the toner image is fixed is
9 is discharged onto a discharge tray 220 from a discharge port provided on an outer wall of the discharge tray 9.

The reading means 230 corresponding to the pattern reading means 8 in FIG. 1 is, as shown in FIG.
Reference numeral 6 denotes a plane state, and is disposed at a position where laser irradiation can be performed perpendicularly to the surface of the transfer conveyance belt 216. As shown partially enlarged in FIG. 9, the reading means 230 includes a semiconductor laser 231, a collimating lens 232, an objective lens 233, a deflecting beam splitter 234, and a focusing lens 23.
5 and a photodiode 236. The laser light emitted from the semiconductor laser 231 passes through the collimator lens 232 and becomes parallel light. After passing through the deflection beam splitter 234, the laser light is narrowed down by the objective lens 233 so as to converge on a minute point on the surface of the transfer conveyance belt 216. It is. The specularly reflected light from the surface of the transfer conveyance belt 216 becomes parallel light through the objective lens 233, and the direction of the reflected light is changed by the deflection beam splitter 234. The reflected light whose direction has been changed is narrowed down by the focusing lens 235 and is incident on the photodiode 236, where signal detection is performed.

As the reading means 230, an optical pickup used in a reproducing apparatus for an optical disk such as a compact disk (CD) or the like can be used. Since the optical pickup is mass-produced, the cost of the reading unit 230 can be reduced. Further, since the image pattern 10 for line width control is formed on the transfer conveyance belt 216, the toner adhered as the toner image 12 or the like to the position where the recording paper 16 is supplied to the transfer conveyance belt 216. Cleaning means 2 for removing water
40 are provided.

In the embodiment described above, the toner image 10 is formed on the surface of the transfer conveyance belt 216 as an image carrier. For a color image, an image pattern 10 is formed for each color to correct control parameters.
If a plurality of colors are superimposed, it is also possible to detect the accuracy of the superposition and readjust. The toner image 10 detected for the control parameter correction is applied to the photosensitive drums 222a and 222a.
Since they are formed on the surfaces of 22b, 222c, 222d and then transferred onto the transfer / conveying belt 16, the photosensitive drums 222a, 222b, 222c, 22 before being transferred.
It is also possible to read directly from the 2d surface. Each photosensitive drum 222a, 222b, 222c, 2
When the image is read directly from the photosensitive drum 2d,
It is possible to easily detect the aging of the 22a, 222b, 222c, and 222d and the change in characteristics due to temperature and humidity, and correct the control parameters appropriately to improve the image quality.

Although a color digital copying machine is described as the image forming apparatus 1, the present invention can be similarly applied to other types of image forming apparatuses such as a monochrome copying machine and a printer. it can.

[0050]

As described above, according to the present invention, it is possible to reduce a noise component included in a detection signal by dividing a continuous detection signal obtained by reading an image pattern and adding the divided signals. The shape of the detected pattern of the image pattern can be calculated with high accuracy. By forming the pattern to be detected so that the line width and dot size can be detected, it is possible to accurately control the line width and dot size necessary for improving image quality, and to control the environment such as temperature and humidity. , And stable gradual change can be obtained with respect to changes in aging and aging.

Further, according to the present invention, the pattern to be detected can be formed periodically, so if the area is divided according to the detection signal, the area is divided in accordance with the pattern to be periodically repeated. The noise component can be reduced using the periodicity.

Further, according to the present invention, since the area width is made to correspond to the predetermined shape of the detected pattern, the position of the detected pattern with respect to the divided area can be kept constant.
Accurate detection of the line width and dot size necessary for improving the image quality can be performed.

Further, according to the present invention, the control of the conditions for forming a recorded image based on the pattern of each color formed in accordance with a plurality of color-separated image information is performed for each color, so that a color image with excellent image quality can be obtained. Can be formed.

Further, according to the present invention, an image pattern including a detected pattern having a predetermined shape is formed on an image carrier provided for each predetermined image color to be separated.
The detection signal that is continuously read for each image color is divided into predetermined areas, the detection signals of each area are added, the shape of the detected pattern is calculated, and the recording image formation Conditions are controlled for each image color. Since the conditions for forming an image on the image carrier corresponding to each image color can be accurately controlled, it is easy to accurately control the line width and dot size necessary for improving the image quality. However, this can be performed for each image color, and stable gradation can be obtained.

[Brief description of the drawings]

FIG. 1 is an image forming apparatus according to an embodiment of the invention.
FIG. 3 is a block diagram showing a schematic configuration of the.

FIG. 2 is a diagram illustrating an example of an image pattern 10 used for line width control in the embodiment of FIG.

FIG. 3 is a graph showing an output value of an image pattern 10 read by the pattern reading means 8 of FIG. 1;

FIG. 4 is a graph showing a result obtained by performing an addition process on the read output value of FIG. 3;

FIG. 5 is a block diagram showing a schematic electrical configuration of a color digital copying machine as the image forming apparatus 1 of the embodiment of FIG. 1;

6 is a block diagram showing a configuration related to an image data input unit 40 and an image processing unit 41 in FIG.

FIG. 7 is a partial plan view showing an operation panel 80 included in the operation board unit 45 of FIG.

FIG. 8 is a front sectional view showing a schematic mechanical configuration of the digital color copying machine of FIG. 5;

FIG. 9 is a simplified perspective view showing a configuration related to a reading unit 230 of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming means 3 Control parameter correction means 4 Area dividing means 5 Addition processing means 6 Control means 7 Addition memory 8 Pattern reading means 10 Image patterns 12, 20 Toner image 14 Blank 16 Conveying belt 18 Recording paper 22, 222a to 222d Photoreceptor drum 24, 224a to 224d Developing device 39 Image forming unit 40 Image data input unit 40a Color CCD 41 Image processing unit 42 Image data output unit 44 CPU 45 Operation board unit 48 Main memory 51 Scanner related control unit 52 Printer Related control unit 80 Operation panel 81 Liquid crystal display device 210 Image forming unit 211 Paper feed mechanism 216 Transfer / transport belt 217 Fixing device 227 Motor 230 Reading means 231 Semiconductor laser 236 Photodiode

Claims (5)

[Claims] 1. An image forming apparatus for forming a recorded image on an image carrier and transferring the image onto a recording member, comprising: a continuous image pattern including a detected pattern having a predetermined shape on the image carrier. A pattern forming means for forming a pattern, a pattern reading means for continuously reading an image pattern formed by the pattern forming means, an area dividing means for dividing a detection signal continuously read by the pattern reading means into a predetermined area, Addition processing means for adding detection signals of the areas divided by the area division means; and calculating the shape of the detected pattern of the image pattern based on the processing result of the addition processing means, and calculating the calculation result with the predetermined shape. A control unit for controlling conditions for forming the recorded image based on a result of the comparison. 2. The image forming apparatus according to claim 1, wherein the pattern forming unit forms the image pattern so that a plurality of predetermined unit pattern images are continuously formed at predetermined intervals, and the area dividing unit includes: 2. The image forming apparatus according to claim 1, wherein the area is divided according to a detection signal that is continuously read from the image forming apparatus. 3. The area dividing unit determines a width of an area to be divided according to a predetermined shape of a detected pattern of the image pattern.
The image forming apparatus as described in the above. 4. The recording image is a color image formed by superimposing images of respective colors formed in accordance with a plurality of pieces of color separation image information, wherein the pattern forming means determines the image pattern as a predetermined pattern of each color. The control means calculates the shape of the pattern to be detected from the image pattern of each color, and controls the conditions for forming a recorded image based on the calculation result for each color. The image forming apparatus according to claim 1, wherein: 5. A color recording image is formed on an image carrier provided for each predetermined image color to be color-separated, and the recording images formed for each image color are superimposed and transferred onto a recording member. In the image forming apparatus, a pattern forming unit that forms a continuous image pattern including a pattern to be detected having a predetermined shape on an image carrier for each image color, and is provided for each image carrier of each image color. Pattern reading means for continuously reading an image pattern formed by the pattern forming means; and area dividing means for dividing a detection signal continuously read by the pattern reading means into a predetermined area for each image color; Addition processing means for adding the detection signals of the areas divided by the area division means for each image color; and processing of the image pattern based on the processing result of the addition processing means for each image color. Control means for controlling the conditions for forming the recorded image for each image color based on the result of calculating the shape of the output pattern and comparing the calculation result with the predetermined shape. apparatus.