JP2002086796A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus having a system for transferring data without being affected by the arrangement or the operating mode of an LD control board and without causing increase of circuit scale or troublesome control. SOLUTION: In an imaging apparatus where sub-scanning resist is regulated by an operation start signal from a resist sensor at a timing up to start of electrostatic latent image forming operation and a next operation start signal becomes active during formation of an electrostatic latent image, a main scanning sync signal, a validity time signal of image, and a line data sync signal synchronized with image data for each line at least during the validity time signal is active are employed for data transfer.

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 a printer or a digital copying machine for performing optical writing and data transfer.

[0002]

2. Description of the Related Art A sub-scanning resist is adjusted by an operation start signal from a registration sensor and a timing until the start of an electrostatic latent image forming operation. As an image forming apparatus in which a start signal becomes active, for example, there is a color image forming apparatus called a tandem type in which image forming units are arranged along a conveyor belt.

Such an image forming apparatus has a tandem configuration in which image data is taken from an image input device and a timing control between colors is performed, and an LD control board (hereinafter, LDB) for each color is used. It is necessary to match the timing with the image input device and the timing with the LDB of each color.

Therefore, in this type of image forming apparatus, (A) the writing position in the sub-scan is determined by the timing delay from the reference registration sensor to the start of writing. The timing of the data request to the image input device and the start timing of FGATE to the LDB must be synchronized with the rotation of the polygon mirror. (B) In order to realize high-speed operation, a method has been used in which a plurality of LDs simultaneously form a plurality of lines of electrostatic latent images. In addition, the writing resolution is increased, and writing finer than the resolution of the original image may be performed.
In B, the double density processing may be performed.

[0005] By the way, the circuit for acquiring image data from the image input device and controlling the timing between the colors corresponds to various configurations and operation modes of the write LDB as described above. This is not preferable because of the complicated operation.

Accordingly, an object of the present invention is to provide an image forming apparatus having a data transfer method which guarantees the operation (A) and solves the problem (B).

[0007]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention comprises an operation start signal from a registration sensor and a start of an electrostatic latent image forming operation. Adjust the sub-scan registration at the timing,
In an image forming apparatus in which the next operation start signal is activated during the formation of an electrostatic latent image, a main scanning synchronization signal;
Data transfer is performed using an image valid period signal and a line data synchronization signal synchronized with image data for each line at least while the image valid period signal is active.

According to a second aspect of the present invention, in order to achieve the above object, in the image forming apparatus of the first aspect, an image delay in a sub-scanning direction is controlled based on the main scanning synchronization signal. And

According to a third aspect of the present invention, in order to achieve the above object, in the image forming apparatus of the first aspect, the image effective period signal length is controlled based on the line data synchronization signal. And

According to a fourth aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to any one of the first to third aspects, the line data synchronization signal is the same as the main scanning synchronization signal. It is characterized by including a timing pulse.

According to a fifth aspect of the present invention, in order to achieve the above object, in the image forming apparatus according to any one of the first to third aspects, the line data synchronization signal has a different timing with respect to the main scanning synchronization signal. Characterized by including the following pulses.

According to a sixth aspect of the present invention, in order to achieve the above object, in the image forming apparatus of the fifth aspect, the timing of the pulse is variable.

According to a seventh aspect of the present invention, in order to achieve the above object, in the image forming apparatus of the fifth aspect, the line data synchronizing signal corresponds to the number of beams of a laser diode forming an electrostatic latent image. It is characterized in that it includes a pulse having a different timing.

According to an eighth aspect of the present invention, in order to achieve the above object, in the image forming apparatus of the fourth aspect, the line data synchronizing signal thins out a pulse according to a sub-scanning double density. It is characterized by the following.

According to a ninth aspect of the present invention, there is provided an image forming apparatus according to the fourth or fifth aspect, wherein the above object is achieved.
The line data synchronization signal includes a pulse having a timing corresponding to the number of beams of a laser diode forming an electrostatic latent image and the number of times of sub-scanning density.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing a tandem type color image forming apparatus to which the present invention is applied. This image forming apparatus is a color image forming apparatus called a tandem type in which image forming units are arranged along a conveyor belt, and an operation start signal from a registration sensor and a sub-scanning resist are registered at a timing until an electrostatic latent image forming operation is started. During the adjustment and the formation of the electrostatic latent image, the next operation start signal becomes active.

This image forming apparatus has different colors (yellow: Y, magenta: M, cyan: C, black: K).
Are formed in a line along a transport belt 102 that transports the transfer paper 101. The transport belt 102 includes a transport roller 10, one of which is a driving roller that is driven and rotated and the other is a driven roller that is driven and rotated.
3 and 104, and is rotationally driven in the direction of the arrow in the figure by the rotation of the transport roller.

A transfer paper 10 is provided below the transport belt 102.
1 is provided. The transfer paper at the uppermost position among the stored transfer papers 101 is
At the time of image formation, paper is fed and is attracted onto the transport belt 102 by electrostatic attraction. The attracted transfer paper 101 is conveyed to the first image forming unit (yellow), where yellow image formation is performed.

The first image forming section (yellow) includes a photosensitive drum 106Y and a charger 107Y, an exposing unit 108, a developing unit 109Y disposed around the photosensitive drum 106Y.
It comprises a photoreceptor cleaner 110Y. After the surface of the photoconductor drum 106Y is uniformly charged by the charger 107Y, the surface is exposed to the laser beam 111Y corresponding to the yellow image by the exposure device 108 to form an electrostatic latent image.

The formed electrostatic latent image is developed by the developing device 109Y, and a toner image is formed on the photosensitive drum 106Y. The toner image is transferred to the transfer paper 101 by the transfer device 112Y at a position (transfer position) where the toner image contacts the photosensitive drum 106Y and the transfer paper 101 on the conveyor belt 102, and a single color (yellow) image is formed on the transfer paper 101. I do. The unremoved toner remaining on the drum surface of the photoreceptor drum 106Y after the transfer is cleaned by the photoreceptor cleaner 110Y to prepare for the next image formation.

As described above, the transfer paper 101 on which the single color (yellow) has been transferred in the first image forming portion (yellow) is
The sheet is conveyed to the second image forming section (magenta) by the conveying belt 102. Also in this case, the toner image (magenta) formed on the photosensitive drum 106M is transferred onto the transfer paper 101 in the same manner as described above. The transfer paper 101 is further conveyed to a third image forming unit (cyan) and a fourth image forming unit (black), and the toner image formed in the same manner as above is transferred to form a color image.

The transfer paper 101 on which the color image has been formed after passing through the fourth image forming section is peeled off from the conveyor belt 102, the image is fixed by the fixing device 113, and then discharged outside the machine. .

FIG. 2 is a plan view showing an optical unit used in the image forming apparatus according to the present invention. In this unit,
Light beams from the LD unit BK201 and the LD unit Y202 pass through the cylinder lenses 203 and 204,
The light is incident on the lower surface of the polygon mirror 207 by the reflection mirror BK205 and the reflection mirror Y206, and the polygon mirror 207 rotates to deflect the light beam.
Through lens BKC208 and fθ lens YM209,
It is folded back by the first mirror BK210 and the first mirror Y211. On the other hand, the light beams from the LD unit C212 and the LD unit M213 are transmitted to the cylinder lens C2.
14, and enters the upper surface of the polygon mirror 207 through the cylinder lens M215. The polygon mirror 207 rotates to deflect the light beam, and the fθ lens BKC
208 and the fθ lens YM209, the first mirror C
216 and the first mirror M217.

The cylinder mirror BKC218 and the cylinder mirror YM219, and the sensor BKC220 and the sensor Y are located upstream of the writing position in the main scanning direction.
M221, and the light beam passing through the fθ lens BKC208 and the fθ lens YM209 is converted into a cylinder mirror BKC
218 and the cylinder mirror YM219 are reflected and condensed, and are incident on the sensor BKC220 and the sensor YM221. These sensors are synchronization detection sensors for synchronizing in the main scanning direction.

The light beams from the LD unit BK201 and LD unit C212 use a common cylinder mirror BKC218 and sensor BKC220. LD unit Y202 and LD unit M21
The same applies to No. 3. Since light beams of two colors are incident on the same sensor, by changing the incident angles of the light beams of each color to the polygon mirror 207, the timing at which each light beam enters the sensor is changed. They are output as a pulse train in series. As can be seen from the figure, BK and C and Y and M are scanned in opposite directions.

FIGS. 3 and 4 show a lighting timing control section in the image forming apparatus having the above-described configuration. Figure 3 shows LD
FIG. 4 shows an interface between the lighting timing control unit 300 and the LDB 301 for each color, and FIG. 4 shows the timing of the interface in FIG.

The main scanning synchronization signal and the line data synchronization signal are supplied from each LDB to the LD lighting timing control circuit 300.
From the LD lighting timing control circuit 300 to each LDB 301
Is sent an image valid period signal and image data. The main scanning synchronization signal is a signal separated for each color based on the output of the synchronization detection sensor in FIG. 2 and is a signal that is activated once per surface of the polygon mirror 207. The LD lighting timing control circuit 300 generates an image valid period signal based on the operation start signal generated by the system controller 303 based on the output of the registration sensor 302,
The DB 301 is notified of the latent image formation timing.

The LDB 301 generates a line data synchronizing signal every time one line of data is required at least while the image valid period signal is active,
The D lighting timing control circuit 300 is notified. The LD lighting timing control circuit 300 deactivates the image valid period signal after the data transfer for the required number of lines is completed. Through such a series of processing, data transfer becomes possible. At this time, the start timing of the image valid period signal, which particularly indicates the amount of delay of the image, can be realized by generating the timing based on the main scanning synchronization signal as shown in FIG. In particular, this can be realized by generating the image effective period signal length based on the line data synchronization signal as shown in FIG.

FIG. 5 is a block diagram showing another embodiment of the present invention. In the present embodiment, the main scanning synchronization signal 50 is generated by the main scanning synchronization signal generation circuit 500 based on the synchronization detection signal.
1, 502 are generated. Also, the main scanning synchronization signals 501, 5
An output 503 is generated from 02 through a thinning circuit 510 that periodically inactivates the active pulse. The line data synchronizing signal 506 includes a pulse having the same timing as the main scanning synchronizing signals 501 and 502 by selecting the signal 502 or the signal 503 in the synthesizing / selecting circuit 511.

A signal 504 obtained by delaying the output of the main scanning synchronizing signal generation circuit 500,
There is an output 505 through a decimation circuit 513 that periodically inactivates the active pulse of the second output. The line data synchronization signal 506 can include a pulse having a timing different from that of the main scanning synchronization signals 501 and 502 by selecting the signal 504 or the signal 505 in the combining / selecting circuit 511. Further, by configuring the delay circuit 512 in FIG. 5 such that the delay amount is determined based on the value of the delay amount setting register 514, the pulse timing of the signal 504 becomes variable.

Another operation of this embodiment will be described with reference to FIGS. FIG. 6 shows a main scanning synchronization signal and a line data synchronization signal corresponding to the number of LD beams. In the example of FIG. 6, the double density operation of the sub-scan is not performed. At the time of one-beam writing, the data required in the LDB 301 is one line per one surface of the polygon mirror 207.
The main scanning synchronization signals 501 and 502 and the line data synchronization signal 506 may be the same. That is, the signal 502 in FIG. 5 may be selected and output as the signal 506. In the case of two-beam writing, since the data required in the LDB 301 is two lines per one surface of the polygon mirror 207, two line data synchronization signals 506 are required for each main scanning synchronization signal. Therefore, for example, the signal 502 in FIG.
06 may be output. At the time of four-beam writing, since the data required in the LDB 301 is four lines per one surface of the polygon mirror 207, four line data synchronization signals 506 are output for each main scanning synchronization signal.
Times needed. Although not shown in FIG. 5, a plurality of delay circuits 512 in FIG. In this way, a pulse having a timing different from that of the main scanning synchronization signal is included in the line data synchronization signal according to the number of beams of the LD.

Another operation of this embodiment will be described with reference to FIGS. FIG. 7 shows a main scanning synchronizing signal and a line data synchronizing signal according to the sub-scanning density. In addition,
In the example of FIG. 7, the number of LD beams is one. In the case of single scanning, the data required in the LDB 301 is one line per one surface of the polygon mirror 207. Therefore, the main scanning synchronization signals 501 and 502 and the line data synchronization signal 506 may be the same. That is, the signal 502 in FIG. 5 may be selected and output as the signal 506. In the case of double density in the sub-scanning direction, the data required in the LDB 301 is one line per two surfaces of the polygon mirror 207. Therefore, one line data synchronization signal 506 is required for every two main scanning synchronization signals. Therefore, for example, in the thinning circuits 510 and 513 in FIG. 5, the thinning may be performed once every two times and output as the signal 506.
When the sub-scanning is 4 times denser, the data required in the LDB 301 is one line per four surfaces of the polygon mirror 207, so one line data synchronizing signal 506 is required for every four main scanning synchronizing signals. Therefore, for example, FIG.
In the thinning circuits 510 and 513 in the above, thinning may be performed at a rate of three out of four times and output as a signal 506. In this way, the line data synchronizing signal includes the pulse thinning at the same timing as the main scanning synchronizing signal according to the sub-scanning density.

Another operation of this embodiment will be described with reference to FIGS. FIG. 8 shows a main scanning synchronizing signal, a line data synchronizing signal corresponding to the number of LD beams and the number of sub-scanning densities. For two-beam, sub-scan, single-density writing, use LD
The data required in B301 is the polygon mirror 20
7, two lines are required for one main scanning synchronization signal, so that the line data synchronization signal 506 is required twice. Thus, for example, the signal 502 in FIG. 5 and the output 504 of the delay circuit may be combined and output as the signal 506. In the case of 2-beam / sub-scan triple density writing, L
The data required in the DB 301 is the polygon mirror 2
07, two lines are required for each three planes, so three line scanning signals are required for three main scanning synchronization signals. Therefore, for example, the output of the signal 503 (thinning out three times) and the output of the signal 505 (thinning out three times) in FIG. In the case of 4-beam / sub-scan single-density writing, the data required in the LDB 301 is equivalent to four lines per one surface of the polygon mirror 207.
The line data synchronization signal 506 is required four times. Therefore, for example, although not shown in FIG. 5, three delay circuits 512 in FIG. 5 may be provided, combined, and output as the signal 506. In the case of 4-beam, sub-scan, triple-density writing, the data required in the LDB 301 is four lines per three surfaces of the polygon mirror 207, so that the line data synchronization signal 506 is four times per three main scanning synchronization signals.
Times needed. Therefore, for example, the signal 503 in FIG.
5 (thin decimated twice) and signal 505 (thin decimated twice), and although not shown in FIG. 5, two more delay circuits similar to the circuit generating signal 505 are provided. 4
The two signals may be combined and output as signal 506.
In this manner, a pulse having the same timing as the main scanning synchronization signal and a pulse having a different timing are included in the line data synchronization signal according to the number of LD beams and the number of sub-scanning densities.

[0034]

As described above, in the image forming apparatus according to the first to third aspects, the polygon control signal for adjusting the start timing of the sub-scan and the LD control board request one line of data. Data signals can be transferred independently without increasing the circuit scale or complicating the control without being affected by the configuration or operation mode of the LD control board. This has the effect.

According to the image forming apparatus of the present invention, as described above, since the image data synchronizing signal has the same timing as the polygon synchronizing signal, the write operation of the LD and the data transfer are synchronized, and the LDB is There is an effect that the above control is simplified and the circuit scale can be reduced.

In the image forming apparatus according to the fifth aspect, as described above, since the image data synchronization signal can take a different timing from the polygon synchronization signal, the data transfer method with a higher degree of freedom can be achieved. There is an effect that it can be realized.

According to the image forming apparatus of the sixth aspect, as described above, there is an effect that it is possible to avoid restrictions on data transfer existing in various operation modes.

According to the image forming apparatus of the present invention, as described above, by performing data transfer for a plurality of lines in accordance with the number of LD beams during the polygon synchronizing signal period, high-speed optical writing can be performed. There is an effect that it can be realized.

According to the eighth aspect of the present invention, as described above, the transfer density can be reduced according to the sub-scanning density, and the image forming apparatus is compatible with the polygon synchronization signal. The control on the LDB is simplified, and the circuit scale can be reduced.

According to the image forming apparatus of the ninth aspect, as described above, it is possible to realize complicated data transfer caused by the combination of the number of LD beams and the number of sub-scanning densities, thereby increasing the degree of freedom in design. There is.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a tandem type color image forming apparatus to which the present invention is applied.

FIG. 2 is a plan view showing an optical unit used in the image forming apparatus according to the present invention.

FIG. 3 is a diagram illustrating an interface between an LD lighting timing control unit and an LDB of each color used in the image forming apparatus according to the present invention.

FIG. 4 is a diagram showing the timing of the interface in FIG. 3;

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing a main scanning synchronization signal and a line data synchronization signal according to the number of LD beams in the embodiment of FIG. 5;

FIG. 7 is a diagram illustrating a main scanning synchronization signal and a line data synchronization signal according to a sub-scanning double density in the embodiment of FIG. 5;

8 is a diagram showing a main scanning synchronization signal and a line data synchronization signal according to the number of LD beams and the number of sub scanning double densities in the embodiment of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Transfer paper 102 Transport belt 103, 104 Transport roller 105 Paper feed tray 106 Photoconductor drum 107 Charger 108 Exposure unit 109 Developing unit 110 Photoconductor cleaner 111 Laser beam 112 Transfer unit 113 Fixing unit 201 LD unit BK 202 LD unit Y 203 , 204 cylinder lens 205 reflection mirror BK 206 reflection mirror Y 207 polygon mirror 208 fθ lens BKC 209 fθ lens YM 210 first mirror BK 211 first mirror Y 212 LD unit C 213 LD unit M 214 cylinder lens C 215 cylinder lens M 216 First mirror C 217 First mirror M 218 Cylinder mirror BKC 219 Cylinder mirror YM 220 Sensor BKC 221 Sensor YM 220 Sensor BKC 300 LD Light timing control unit 301 LDB 302 Registration sensor 303 System controller 500 Main scanning synchronization signal generation circuit 501, 502 Main scanning synchronization signal 503 Output 504 Signal 505 Output 506 Line data synchronization signal 510 Decimation circuit 511 Synthesis / selection circuit 512 Delay circuit 513 Decimation Circuit 514 Delay amount setting register

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 BA52 BA69 BA70 BA71 BB34 BB38 BB46 CA22 CA39 CB74 DA09 2H045 AA01 BA22 BA34 CA98 5C072 AA03 BA19 HA02 HA06 HB08 HB11 HB13 NA04 NA08 QA14 XA01 XA05 5C074 AA DD DD GG09 HH02

Claims (9)

[Claims] A sub-scanning resist is adjusted at a timing until an operation start signal from a registration sensor and the start of an electrostatic latent image forming operation, and the next operation start signal becomes active during the formation of the electrostatic latent image. In the image forming apparatus, data transfer is performed using a main scanning synchronization signal, an image valid period signal, and a line data synchronous signal synchronized with image data of each line at least while the image valid period signal is active. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein an image delay in a sub-scanning direction is controlled based on the main scanning synchronization signal. 3. The image forming apparatus according to claim 1, wherein the image valid period signal length is controlled based on the line data synchronization signal. 4. The image forming apparatus according to claim 1, wherein said line data synchronization signal includes a pulse having the same timing as a main scanning synchronization signal. 5. The image forming apparatus according to claim 1, wherein the line data synchronization signal includes a pulse having a different timing from the main scanning synchronization signal. 6. The image forming apparatus according to claim 5, wherein the timing of the pulse is variable. 7. The image forming apparatus according to claim 5, wherein the line data synchronization signal includes a pulse having a timing corresponding to the number of beams of a laser diode forming an electrostatic latent image. 8. The image forming apparatus according to claim 4, wherein the line data synchronization signal thins out a pulse corresponding to a sub-scanning density. 9. The image forming apparatus according to claim 4, wherein the line data synchronization signal includes a pulse having a timing corresponding to the number of beams of a laser diode for forming an electrostatic latent image and the number of sub-scanning densities. An image forming apparatus comprising: