JP2000134418A - Image forming device and control method for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a color image with high quality by eliminating color slurring caused by dispersion in an original read position due to a timing deviation in rising of a motor that drives an original read section or a slacked belt that delivers a torque of the motor to the original read section. SOLUTION: A edge sensor 504 senses that a CCD reads a start trigger line through the scanning by a mirror stand on which a halogen lamp and a mirror are mounted. When a timer 503 and a CPU 501 control an original read start by the CCD and start of image forming by a printer control section 502 based on the start trigger line detection timing is controled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reading section for reading image data for each color component by scanning a document placed on a document table for each color component, and an image for each color component read by the reading section. The present invention relates to an image forming apparatus having an image forming unit for forming a multi-color image by sequentially superimposing color component images based on data, and a control method of the image forming apparatus.

[0002]

In recent years, a copier has been required to have more precise control in accordance with the increase in speed and image quality. In particular, in the case of a color copying machine in which a document is scanned a plurality of times for each color component, a reader unit serving as an image reading unit of the copying machine needs to synthesize read image data of each component. Therefore, if the timing for writing the image data to the image forming unit is not accurately set, the image data for each color is synthesized with a shift, which is a factor of deteriorating the image quality.

[0003] Possible causes of the deterioration in accuracy include variations in the reader start timing due to the accuracy of the timer for controlling the reader, and variations in the start position due to the deflection of the belt that transmits the power of the motor driving the reader to the reader.

In a copying apparatus having such variations, even if the reader and the image forming apparatus are started in synchronization with the timing determined for each color, the read image is not completely synthesized between the color components. This was the cause of the gap.

FIG. 9 is a timing chart showing the operation timing of a conventional image forming apparatus, and corresponds to a copying operation of a color copying machine that makes a copy by scanning a document a plurality of times.

First, when a copy start signal is input at a timing 101, a start trigger signal (hereinafter referred to as a synchronizing signal) for driving a document scanner unit for document reading scan, reading an image, and printing the read image is synchronized. , Trigger signal) is generated at timing 102, and the optical scanner unit
The image is read at timing 104 and the printing operation is synchronized at timing 105.

In the above-described conventional method of synchronizing, if the optical motor driver varies in the read timing and the read start position for the reasons described above, the image read timing and the write timing of the copy image are changed. Since there is no coincidence in scanning for each color component, there is a problem that the color of the copied image is shifted and the quality of the image is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the first to fifth inventions according to the present invention to provide a scanner which a reading unit passes through for scanning an original. Detects that a predetermined reference mark provided at a position readable before the document has been read on the path and after the scanning of the reading unit has started, and based on the reference mark detection timing, the reading unit By controlling the start of document reading and the start of image formation by the image forming unit, the document reading position due to the timing shift at the time of startup of the motor driving the document reading unit and the slack of the belt transmitting the motor drive to the document reading unit FORMING APPARATUS AND IMAGE FORMING APPARATUS CAPABLE OF FORMING HIGH QUALITY COLOR IMAGES BY RESOLVING COLOR DISPLACEMENT DUE TO VARIATIONS There is provided a control method.

[0009]

According to a first aspect of the present invention, there is provided a reading section (see FIG. 1) which scans a document placed on a document table 201 for each color component to read image data for each color component. Halogen lamp 202, mirror 203,
The CCD 207, a mirror base 305 shown in FIG. 2, and an image forming unit (laser shown in FIG. 1) for sequentially superimposing color component images based on image data for each color component read by the reading unit to form a multicolor image. In the image forming apparatus including the irradiation device 208, the photosensitive drum 209, the developing devices 210 to 213, and the transfer drum 215), the scanning unit starts scanning on the scanning path through which the reading unit passes to scan the original. A predetermined reference mark (start trigger line 405 shown in FIG. 3) provided at a position where it can be read before the original later, and a detecting means (detecting that the reading unit has read the predetermined reference mark) An original is read by the reading unit based on an edge sensor 504 shown in FIG. 4) and a reference mark detection timing of the detection unit. Start and control means for controlling the image formation start by the image forming unit for each color component (shown in FIG. 4, CPU 501, the printer control unit 502, a timer 50
3).

A second invention according to the present invention is directed to the control means (CPU 501, printer control unit 502,
The timer 503) starts reading of the original by the reading unit and image formation by the image forming unit after a predetermined time has elapsed after the detection of the reference mark by the detecting unit for each color component.

According to a third aspect of the present invention, there is provided the control means (CPU 501, printer control unit 502,
The timer 503) measures the time from the start of scanning by the reading unit to the detection of the reference mark by the detecting unit for each color component, and based on the time measurement result, starts reading of the original by the reading unit and forms the image. This is to change the start of image formation by the copy unit.

According to a fourth aspect of the present invention, the predetermined reference mark (start trigger line 405 shown in FIG. 3)
Is a straight line that is black and perpendicular to the scanning direction of the reading unit.

According to a fifth aspect of the present invention, there is provided a reading section for reading an image data for each color component by scanning a document placed on a document table for each color component, and for each color component read by the reading section. In the control method of an image forming apparatus having an image forming unit that sequentially superimposes color component images based on the image data to form a multicolor image, the reading unit passes through the reading unit to scan the original. A detection step of detecting that a predetermined reference mark provided at a position readable on the scanning path and before the original after the scanning of the reading unit is started (FIG. 5)
Step (5), step (3) in FIG. 6, timing 804 in FIG. 7, and a document reading step (step (6) in FIG. 5) in which the reading unit starts reading the document based on the reference mark detection timing. )) And an image forming step of starting image formation by the image forming unit based on the reference mark detection timing (steps (4) and (4) in FIG. 6).
7 (timing 808 in FIG. 7).

[0014]

FIG. 1 is a cross-sectional view illustrating the structure of a color copying machine to which an image forming apparatus according to an embodiment of the present invention can be applied.

In FIG. 1, reference numeral 201 denotes a platen glass;
A halogen lamp 02 irradiates a document placed on the document table 201. Reference numerals 203, 204, and 205 denote mirrors, and a CCD image sensor (CCD) 20 serving as a photoelectric device for passing a document image placed on a document table 201 illuminated by a halogen lamp 202 through a lens 206.
7 is input.

The halogen lamp 202 and the mirror 2
Numeral 03 scans the entire original by moving integrally, and inputs an image of the entire original to the CCD 207. CCD
Reference numeral 207 converts the original image obtained via the lens 206 into a voltage, and outputs a laser power input value proportional to the density of the input original image to the laser irradiation device 208.

The CCD 207 switches the wavelength range of the light to be read, so that the color components magenta (M), cyan (C), yellow (Y), black (B
k) is read independently.

The laser irradiator 208 irradiates the photosensitive drum 209 with a laser beam having an intensity corresponding to the voltage level input from the CCD 207, thereby causing the photosensitive drum 209 to emit laser light.
To form a latent image of the read image.

Reference numerals 210, 211, 212, and 213 denote developing devices which are arranged around the photosensitive drum 209,
10 stores magenta toner, developing device 211 stores cyan toner, developing device 212 stores yellow toner, and developing device 213 stores black toner. Is photosensitive drum 2
09, and adheres on the photosensitive drum 209 in an amount proportional to the laser intensity applied to the photosensitive drum 209.

Reference numeral 214 denotes a charger, which is a laser irradiation device 208.
Irradiates the latent image formed on the photosensitive drum 209. 216 is a copy sheet as a recording medium, 217 is a sheet tray, and stores the copy sheet 216. A transfer drum 215 includes rollers 218, 219, and 2
The copy paper 216 guided by the transport path 20 and transported on the transport path 221 is electrostatically attracted onto the transfer drum 215, and the toner adhered on the photosensitive drum 209 is transferred to the copy paper on the transfer drum 215.

Reference numeral 223 denotes a fixing roller, which includes magenta (M),
After the respective toners of cyan (C), yellow (Y), and black (Bk) are transferred, the toner is fixed on the copy paper conveyed through the conveyance path 222, and is discharged onto the paper discharge tray 224. .

FIG. 2 shows the halogen lamp 20 shown in FIG.
FIG. 2 is a diagram illustrating a configuration of a reader unit that moves a mirror 2 and a mirror 203, and the same components as those in FIG. 1 are denoted by the same reference numerals.

In the figure, reference numeral 301 denotes a motor,
The wire 304 wound around the roller 303 through
Is moved to move the mirror base 305.
The mirror base 305 includes the halogen lamp 202 and the mirror 2.
03 is mounted, and the wire 304 is horizontally wound on the rail 306 by being wound by the roller 303.

FIG. 3 shows the platen glass 201 shown in FIG.
FIG. 2 is a diagram for explaining the configuration of the left side of the glass as viewed from the back side (the lower side in FIG. 1), and the same components as those in FIGS.

Referring to FIG. 1, reference numeral 401 denotes a platen glass area on which a document is placed. An arrow 403 indicates a direction in which the mirror table 305 moves when reading a document. The document is placed only in the range of the platen glass area 401, but the mirror table 305 can start reading an image from the left end of the area 404 on the left side of the platen glass.

Reference numeral 405 denotes a start trigger line, which is a black line written on the non-document area 404. The non-document area 404 is a CCD except for the start trigger line 405.
It is white so that the input level to 207 becomes LOW. Reference numeral 406 denotes a home position of the mirror base, and the mirror base 305 is always located at the home position 40 before the copy is started and after the image reading scan for each color component is completed.
Return to 6.

FIG. 4 is a block diagram showing a control configuration of the color copying machine shown in FIG.

In the figure, reference numeral 501 denotes a CPU, which is a reader unit (motor 301, mirror base 305, CCD 207).
Etc.). The CPU 501 communicates with the printer control unit 502 that controls the latent image, development, fixing, and paper conveyance via an interface 506.
The output data and the like of the CCD 207 are transmitted.

Reference numeral 503 denotes a delay timer (hereinafter, timer).
A reset input terminal, a delay value input terminal, a start input terminal, and a trigger output terminal.
0, a delay value via the interface 511, a start signal via the interface 508, and a trigger output via the interface 507 to the CPU 501 and the printer controller 50.
Output to 2.

The timer 503 has a function of outputting a trigger signal after counting according to a delay value when a start signal is input while a delay value is set and a reset terminal is input. .

In the configuration of the present embodiment, the timer 503 starts counting by inputting a signal output from the edge sensor 504 via the interface 508. The edge sensor 504 outputs the output value 50 of the CCD 207.
5 is captured via the interface 509, and when a change occurs, a start signal is output to the timer 503.

The CPU 501 executes a program stored in the ROM 520 or another storage medium (not shown) to control the entire copying machine. 521 is a RAM,
Used as a work area of the CPU 501.

Further, the printer control unit 502 includes a CPU, a ROM, and a RAM (not shown) therein, and executes a program stored in the ROM or another storage medium (not shown) to perform overall control of the printing operation.

Hereinafter, referring to the flowchart of FIG.
The document reading processing operation of the image forming apparatus of the present invention will be described.

FIG. 5 is a flowchart showing a first control processing procedure of the image forming apparatus according to the present invention. The flowchart corresponds to a document reading processing procedure, and is executed by the CPU 501 according to a program stored in the ROM 520 or another storage medium (not shown). It is executed based on. Note that (1) to (6) indicate each step.

First, the timer 503 is reset (1),
A predetermined count value is set in the timer 503 (2).
This count value corresponds to the mirror table 305 from the home position 406 to the left end of the platen glass 201 on which the sheet is placed.
Is the time needed to move. Wait until the copy starts (3), and when the copy starts,
The mirror base 305 is driven (4). Before driving, the mirror base 305 always returns to the home position 406 at the left end of the non-document area 404.

The mirror base 305 starts moving and the CCD 207
Waits for an image to be read (5) until a trigger signal generated after counting a predetermined time after detection by the timer 503 is input (timer interrupt) based on the detection of the start trigger line 405 by (5). , CC
Image reading by D207 is started (6).

Hereinafter, referring to the flowchart of FIG.
The print processing operation of the image forming apparatus of the present invention will be described.

FIG. 6 is a flowchart showing a second control processing procedure of the image forming apparatus according to the present invention, which corresponds to a print processing procedure, in which the CPU 501 and the CPU in the printer control unit 502 control the ROM 520 and the printer control unit 502. Is executed based on a program stored in a ROM or another storage medium (not shown). (1) to (4)
Indicates each step.

First, the developing units 210 to 213 of the printing unit
The position of the photosensitive drum 209 is initialized (1), and the process waits until copying is started (2). When copying is started, the mirror base 305 starts moving, and the CCD 207 is started.
Waiting for a copy sheet to be fed and printed until a trigger signal generated after a predetermined time count is detected (timer interrupt) based on the detection of the start trigger line 405 by the timer 503 (3). When the input is made, the paper feeding and printing process of the copy paper is started (4).

The processing of steps (4) to (6) in FIG. 5 and steps (3) and (3) in FIG.
By performing the process (4), a color image without color shift can be formed.

FIG. 7 is a timing chart showing the operation timing of the image forming apparatus of the present invention, which corresponds to the timing from the start of copying to the reading of the first color component (magenta) and the printing. .

First, when copying is started at timing 801, the mirror base 305 starts reading drive from the home position 406 at timing 802. At the same time, at timing 806, input of an image to the CCD 207 starts. Mirror base 305 is start trigger line 40
When the signal passes through 5, the signal input level of the CCD 207 changes as shown by the timing 803 (the rising timing of the arrow at the timing 803). Therefore, as shown by the timing 804, the start signal is input to the timer 503 by the edge sensor 504.

After measuring a preset count value, the timer 503 outputs a trigger signal to the CPU 501 at a timing 805. CP that input trigger signal
U501 starts outputting the output of the CCD 207 to the laser irradiation device 208 at timing 808, and the printer control unit 502 rotates the transfer drum 215 at timing 807, feeds the copy paper 216, and pastes it on the transfer drum 215. At the same time, the photosensitive drum 209 is rotated to start the latent image.

When the mirror table 305 has read up to the right end of the document table, the mirror table 305 returns to the home position, and starts driving to read the next color component (cyan (C) in this embodiment) after a predetermined time. The mirror base 305 is driven to start
Since other copy operations are not started until the trigger line 405 is read, the interval from the end of reading to the reading of the next color component may be set arbitrarily.

As described above, by adjusting the synchronization trigger of the copy operation to the mark reading timing of the mirror base 305, the deviation of the start timing of the mirror base 305,
It is possible to absorb variations in the start position, etc.
Color shift, a major problem with conventional color copiers,
It can be easily and inexpensively solved.

The image reading timing 80 shown in FIG.
In No. 6, the image can always be read after the copy start, but after reading the start trigger line 405, the reading is temporarily interrupted and the start trigger line 40 is read.
After a certain period of time has elapsed from the reading of No. 5, it may be configured to restart in synchronization with a trigger signal (timing 805). The timing chart is shown below.

FIG. 8 is a timing chart showing a second operation timing of the image forming apparatus according to the present invention. The timing from the start of copying until the first color component (magenta) is read and printed. Corresponding to

In this embodiment, the timer 503 is
For each color component, counting is started by inputting a signal output from the edge sensor 504, and after counting according to a set delay value, a trigger signal is output.
The case where reading of an original and image formation for each color component are started has been described, but the time from when the timer 503 starts the reader unit to when a detection signal is input from the edge sensor 504 (from when the start trigger line 405 is read) ) May be counted, and based on the count result, the timing of starting reading of the document and forming the image may be changed for each color component. The timing of starting the reading of the original and the image formation is determined by a timer 50.
The timing is such that the delay or advance of the reader unit calculated based on the count value of 3 is canceled.

Further, the present invention can be applied to an image forming apparatus of an electrophotographic type, an ink jet type, a sublimation type, and other types.

As described above, an image is formed in the area (non-document area 404) on the back side of the document glass 201 on which the document is sandwiched and before the mirror table 305 passes to read the image area (document area 401). A mark (start trigger line 405) is provided as a reference for the timing of reading, and after a certain period of time has elapsed after the reader unit has read the mark, document reading and image formation are started, so that the color component of the document reading portion for each color component is read. The synthesizing timing of the image data can be matched.

Therefore, since the timing of document reading and image formation is synchronized after the start of the reader unit, the color shift caused by the timing shift at the time of startup of the reader unit drive motor (motor 301) is eliminated. And a high-quality color image can be formed.

As described above, the storage medium storing the program codes of the software for realizing the functions of the above-described embodiment is supplied to the system or the apparatus, and the computer (or the CPU or the MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads out and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, C
DR, magnetic tape, nonvolatile memory card, RO
M, EEPROM and the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also an OS (Operating System) running on the computer based on the instruction of the program code. ) And the like perform part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

The present invention may be applied to a system constituted by a plurality of devices or to an apparatus constituted by a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. .

Further, by downloading and reading a program represented by software for achieving the present invention from a database on a network by a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

[0060]

As described above, the first embodiment according to the present invention is described.
According to the invention, a reading unit that reads image data for each color component by scanning a document placed on a document table for each color component, and a color component based on the image data for each color component read by the reading unit In an image forming apparatus having an image forming unit for sequentially superimposing images to form a multicolor image, the document may be scanned on a scanning path through which the reading unit passes to scan the document, and after the scanning unit starts scanning. The detecting means detects that a predetermined reference mark provided at a position which can be read earlier is read, and based on the reference mark detection timing of the detecting means, the control means starts the reading of the original by the reading unit and the Since the start of image formation by the image forming unit is controlled for each color component, the timing deviation at the time of startup of the motor driving the document reading unit. It is possible to eliminate the color shift caused by variations in the document reading position by slack of the belt for transmitting the drive of the motor to the document reading section.

According to the second invention, the control means performs, for each color component, reading of the original by the reading unit and image formation by the image forming unit after a lapse of a predetermined time after the detection of the reference mark by the detecting unit. To start,
Image reading and image formation are performed at a certain timing with respect to the reference mark, so that an image without color shift can be formed.

According to the third aspect, the control means measures, for each color component, the time from the start of scanning by the reading unit to the detection of the reference mark by the detection means, and based on the time measurement result, Since the start of reading of the document by the reading unit and the start of image formation by the image forming unit are changed, the timing shift at the time of startup of the motor driving the document reading unit and the slack of the belt transmitting the driving of the motor to the document reading unit are caused. An image with no color shift can be formed by offsetting the variation in the document reading position.

According to the fourth aspect, the predetermined reference mark is black and is a straight line in a direction perpendicular to the scanning direction of the reading unit. Separately, it can be accurately detected.

According to the fifth aspect, a reading section for reading image data for each color component by scanning a document placed on a document table for each color component, and an image for each color component read by the reading section In a control method of an image forming apparatus having an image forming unit that sequentially superimposes color component images based on data to form a multicolor image, a scanning path through which the reading unit passes for the reading unit to scan the document And detecting that a predetermined reference mark provided at a position readable before the document has been read after the scanning of the reading unit has started, and based on the reference mark detection timing, the document by the reading unit is detected. Since reading is started and image formation by the image forming unit is started based on the reference mark detection timing, the mode for driving the document reading unit is set. It is possible to eliminate the color shift caused by variations in the document reading position by slack of the belt for transmitting the drive of the motor to a timing shift or document reading section at the rising edge.

Therefore, it is possible to eliminate the color misregistration caused by the timing deviation at the time of the rise of the motor driving the original reading unit and the variation of the original reading position due to the slack of the belt transmitting the driving of the motor to the original reading unit. This produces the effect that a high-quality color image can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a color copying machine to which an image forming apparatus according to an embodiment of the present invention can be applied.

FIG. 2 is a diagram illustrating a configuration of a reader unit that moves a halogen lamp and a mirror illustrated in FIG. 1;

FIG. 3 is a diagram illustrating a configuration in which a platen glass and a left side of the glass illustrated in FIG. 1 are viewed from the back side.

FIG. 4 is a block diagram showing a control configuration of the color copying machine shown in FIG.

FIG. 5 is a flowchart illustrating a first control processing procedure of the image forming apparatus of the present invention.

FIG. 6 is a flowchart illustrating a second control processing procedure of the image forming apparatus of the present invention.

FIG. 7 is a timing chart showing the operation timing of the image forming apparatus of the present invention.

FIG. 8 is a timing chart showing a second operation timing of the image forming apparatus of the present invention.

FIG. 9 is a timing chart showing operation timing of a conventional image forming apparatus.

[Explanation of symbols]

 201 Platen glass 203 Mirror 202 Halogen lamp 305 Mirror table 405 Start / trigger line 406 Home position 501 CPU 502 Printer control unit 503 Timer 504 Edge sensor 520 ROM 521 RAM

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA23 DA35 DA38 DB06 DE02 DE07 DE10 ED04 EE02 EE04 EE07 EF06 2H030 AA01 AD12 BB02 BB07 BB16 2H076 AA58 BA03 EA16 5C072 AA05 BA19 DA04 EA04 FB23 LA02 QA14 MB06 WA03 XA01

Claims (5)

[Claims] A scanning unit that scans a document placed on a platen for each color component to read image data for each color component; and a color component image based on the image data for each color component read by the reading unit. An image forming apparatus having an image forming unit that sequentially superimposes and forms a multicolor image, on a scanning path through which the reading unit passes to scan the original, and after the reading unit starts scanning, A predetermined reference mark provided at a previously readable position, a detection unit that detects that the reading unit has read the predetermined reference mark, and a reference mark detection timing of the detection unit.
Control means for controlling, for each color component, the start of document reading by the reading unit and the start of image formation by the image forming unit. 2. The method according to claim 1, wherein the control unit starts reading the document by the reading unit and forming an image by the image forming unit after a predetermined time has elapsed after the detection of the reference mark by the detecting unit for each color component. Claim 1
The image forming apparatus as described in the above. 3. The control unit measures, for each color component, the time from the start of scanning by the reading unit to the detection of a reference mark by the detection unit, and based on the time measurement result, the reading unit reads the original. The image forming apparatus according to claim 1, wherein the start and the start of image formation by the image forming unit are changed. 4. The predetermined reference mark is black,
The image forming apparatus according to claim 1, wherein the image forming apparatus is a straight line perpendicular to a scanning direction of the reading unit. 5. A reading section for scanning a document placed on a platen for each color component to read image data for each color component, and a color component image based on the image data for each color component read by the reading section. A control method for an image forming apparatus having an image forming unit for forming a multi-color image by sequentially superimposing a plurality of images, wherein the reading unit is on a scanning path through which the reading unit passes to scan the original, and A detection step of detecting that a predetermined reference mark provided at a position readable before the document has been read after the start of scanning of the document, and reading of the document by the reading unit based on the reference mark detection timing is started. And an image forming step of starting image formation by the image forming unit based on the reference mark detection timing. A method of controlling an image forming apparatus.