JP2002347280A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To interrupt the continuation of waste copying when an abnormal condition occurs during copying. SOLUTION: In an image forming apparatus having a function of determining an abnormal writing condition, counted values of two main scanning counters 31, 32 are compared with each other during the copying. When the counted values are different from each other, it is judged that an abnormal condition occurs in the main scanning counters and the copying is interrupted. When an abnormal condition of a writing clock or a polygon clock is detected during the copying, the copying is interrupted and the clocks are reset to be automatically restored in the normal condition.

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 suitable for use in a digital copying machine or the like in which image information is digitally processed to edit an image and create a latent image double image using light emitting elements.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. Hei 8-252945 discloses a technique for accurately determining an abnormal period of a horizontal synchronizing signal, which is one of the causes of intensive deterioration of a portion of a photoconductor. This is because the synchronization signal abnormality monitoring unit monitors whether the period of the synchronization signal is longer than the reference period, or whether it is normal, and when it is determined that there is an abnormality, continuously turns on the LD and reliably detects light. In this case, the period is accurately detected and the cause of the period abnormality is specified. Further, there has been proposed an image forming apparatus in which, when a writing control error occurs during copying, the cause of the error can be specified. But,
In such an image forming apparatus, even if the cause of the abnormality can be identified during copying, the toner and the like are wastefully consumed to continue the copying. In addition, when copying again, it was troublesome to turn on / off the power.

[0003]

In a conventional copying machine such as a digital copying machine, when a main scanning counter error occurs during copying, a horizontal line is written by, for example, turning on the LD earlier than the original forced lighting position. The first problem was that Further, in a conventional copier, when a write clock error occurs during copying, an abnormal image is output uselessly. In order to recover, the user turns on / off the power.
There was a second problem that it had to be turned off. Further, in a conventional copying machine, when a polygon rotation error occurs during copying, an abnormal image is output uselessly. In addition, there is a third problem that it has to be turned on / off in order to return.

SUMMARY OF THE INVENTION The present invention has been made to solve the first problem, and has as its object to prevent useless copying from continuing when a main scanning counter error occurs. The invention of claim 2 has been made to solve the second problem, and when a write clock abnormality occurs,
It is an object of the present invention to prevent useless copying from continuing and to save a user's trouble by automatically normalizing a write clock. The invention according to claim 3 has been made to solve the third problem. In the event that a polygon rotation error occurs, useless copying is not continued and the polygon clock is automatically made normal. The purpose is to save time and effort for the user.

[0005]

In order to achieve the above object, in an image forming apparatus according to the present invention,
In an image forming apparatus having an abnormality cause identification unit capable of detecting a writing abnormality and identifying the cause of the abnormality and a main scanning counter for measuring a predetermined main scanning period, the abnormality cause identification unit performs main scanning during image formation. A control means for stopping image formation when an abnormality of the counter is detected is provided.

According to a second aspect of the present invention, there is provided an image forming apparatus having an abnormal cause identifying means capable of detecting a writing abnormality and identifying the cause of the abnormality. When an error is detected in the write clock, control means for stopping the image formation, resetting the write clock, and returning to the normal state is provided.

Further, in the image forming apparatus according to the third aspect of the present invention, in the image forming apparatus having an abnormal cause identifying means capable of detecting a writing abnormality and identifying the cause of the abnormality, the abnormal cause identifying means during image formation. When an error is detected in the polygon clock, control means is provided for stopping the image formation, resetting the polygon clock, and returning to the normal state.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a digital copying machine as an image forming apparatus according to an embodiment to which the present invention is applied. The digital copying machine includes a scanner unit 1 for reading a document image, a printer unit 2 for printing, a CPU 3 for controlling the entire apparatus, a ROM 4 for storing a control program, and a RAM for temporarily using the control program.
5, an image memory 6 for storing the read image, an internal system bus 7 for exchanging data between the devices, an I / F 8 for interfacing between the system bus 7 and the IPU 12, a user giving an instruction and a predetermined An operation unit 9 for performing display is provided.

The scanner unit 1 converts the read signal into an A / D signal.
The VPU 11 includes a VPU 11 that performs black offset correction, shading correction, pixel position correction, and the like after conversion, and an IPU 12 that performs image processing of the corrected signal. The printer unit 2 controls the LD control unit 22 based on the image-processed signal.
LD for controlling VD 21 and LD (semiconductor laser) 23
The control unit 22 forms an electrostatic latent image on the photosensitive drum L
D23 and PD (photodetector) 24.

FIG. 2 is a schematic configuration diagram of the writing unit. In FIG. 2, a laser beam emitted forward from an LD 23 is collimated by a collimator lens (not shown), is deflected by a deflector 25 composed of a rotating polygon mirror (polygon mirror), and is deflected by a fθ lens 26 to a photosensitive drum 27. An image is formed on a uniformly charged surface by a charger (not shown). The main scanning is performed by the imaging spot reciprocating in the axial direction on the surface of the photosensitive drum 27 according to the rotation of the deflector 25. The sub-scan is performed by rotating the photosensitive drum 27.

On the other hand, the photodetector 28 is a photosensitive drum 27
, And detects a laser beam deflected by the deflector 25 to generate a DETP signal. GA
The VD 21 inputs the image information signal to the LD drive circuit 221 of the LD control unit 22, and controls the timing with the DETP signal. The LD drive circuits 221 are provided by the number of channels of the LD 23, and drive the LD 23 by an image information signal from the GAVD 21 to form an electrostatic latent image on the photosensitive drum 27. This electrostatic latent image is developed by a developing device and transferred to a transfer paper or the like by a transfer device (both not shown).

The laser beam emitted backward from the LD 23 enters the PD 24 and its light intensity is detected.
The control circuit 222 controls the LD drive circuit 221 according to the light detection signal, whereby APC control for controlling the output light amount of the LD 23 to be constant is performed. Specifically, LD
The driving power supply of each of the 23 light emitting elements is adjusted and held by an external signal so that the output light quantity of each light emitting element becomes constant.

FIG. 3 is a block diagram showing a schematic configuration of the GAVD 21 and its periphery. GAVD21 is IPU12
Memory unit 211 that performs speed conversion and format conversion of the image data processed in step 2, an image processing unit 212 that processes image data from the memory unit 211, and an image processing unit 212
An output data control unit 213 that performs processes such as γ conversion and P sensor pattern assignment on the data processed image data.
Having.

The output data of the output data control unit 213 is sent to the LD control unit 22. The output data control unit 213 is supplied with the clocks CLK1 and CLK2 from the PLL 41 and the PLL 42,
8, a DETP signal is input.

FIG. 4 is a block diagram showing the configuration of the output data control unit 213. In FIG. 4, the DETP signal from the photodetector 28 and the write CLK from the PLL 41
1, the clock control unit 30 performs phase control, and drives two main scanning counters 31 and 32 and a sub-scanning counter 33 for measuring a predetermined main scanning period by the phase-controlled clock. A gate signal is generated in the main / sub scanning gate signal generator 34 based on the output of each counter, and the gate signal is sent to each block.

On the other hand, a P pattern section 35 for providing a P sensor pattern for applying a certain density of toner on the photosensitive drum in order to obtain data for determining process conditions on the image data from the image processing section 212, A gamma converter 36 for changing the weight of data, an image in synchronization with an APC operation timing for keeping the light amount of the LD constant, an application of forced lighting data for detecting a synchronization signal, and an LDON / OFF unit for applying image data 37 are provided. further,
A clock controller 38 that generates a clock whose phase is controlled based on the DETP signal and the CLK2 from the PLL 42, and a monitor signal generator 3 that generates a monitor signal based on the clock.
9. An abnormality monitoring unit 40 for monitoring the DETP signal and the forced lighting signal is provided.

FIG. 5 is a flowchart showing the general operation. In FIG. 5, when the copy is started,
It is checked whether the main scanning counters 31 and 32 are normal (step S1). When it is determined that the main scanning counter is abnormal (step S1 / No), the process jumps to the main scanning counter abnormality routine (step S2), and when it is normal (step S1).
1 / Yes), it is checked whether the forced lighting timing is normal (step S3). If it is determined that the forced lighting timing is abnormal (step S3 / No), the process jumps to the write CLK abnormality routine (step S4), and if normal (step S3 / Yes), the process proceeds to S5. In S5, it is checked whether the DETP signal is normal, and if it is abnormal (step S5 /
No) Jump to the polygon CLK abnormality routine (step S
6) If normal (step S5 / Yes), return.

FIG. 6 shows an operation flowchart of the main scanning counter check. When copying is started, the values of the two main scanning counters 31 and 32 are read (step S1).
1). Compare the two counter values (step S12),
If the result is the same (step S12 / Yes), the process jumps to the forced lighting timing routine (step S13). If the result is different (step S12 / No), the process jumps to the main scanning counter abnormality routine (step S14).

FIG. 7 shows the operation according to the first aspect of the present invention. When an abnormality occurs in the main scanning counter, this routine is entered. First, after copying is stopped (step S21),
The two main scanning counters 31 and 32 are reset (step S22). Then, the fact that the copy has failed and the status is restored to the normal state is displayed by the operation unit 9 (step S23).

FIG. 8 is a timing chart for identifying the cause of the write control abnormality. In FIG. 8, the DETP signal is active low, and DATA is active high. First, forcibly lighting the LD is started to obtain DETP, and when DETP is input, DATA is turned off.
This is performed for each main scan. The synchronization detection monitoring signal and the forced lighting monitoring signal are P
It is generated by CLK2 sent from LL42. When the synchronization detection monitoring signal is high, monitoring is performed, and when DETP is low during that period, it is normal, and when it is not low, it is abnormal. Also, the forced lighting monitoring signal is high.
In the case of, when DATA becomes high, it is determined to be normal.

FIG. 9 is a flowchart of the forced lighting timing detection. After the start, it is checked whether the monitoring timing has been entered (step S31). When the monitoring timing starts (step S31 / Yes), it is checked whether DATA is low (step S32). If DATA is not low (step S32 / No), since it is NG, the process jumps to the write CLK abnormality routine of step S4 in FIG.

If DATA is low (step S32 / Yes), it is checked whether DATA is high (step S33). If DATA is not high (step S33 / No), it is checked whether monitoring timing has been entered (step S34). When the monitoring timing has not been entered (step S34 / No),
The process jumps to the write CLK abnormality routine of step S4 in FIG.
If the monitoring timing has been entered (step S34 /
Yes), and returns to S33. DATA is high in S33
(Step S33 / Yes), it is determined that the result is OK (Step S35), and after resetting (Step S3
6) Check whether the copy is completed (step S)
37). If copying has not been completed (step S3
(7 / No), return to S31, and if completed (step S37 / Yes), end the operation. The DETP monitoring flowchart is substantially the same as that in FIG.

FIG. 10 relates to the second aspect of the present invention, and enters this routine when a write CLK abnormality occurs. First, after the copy is stopped (step S41), the write CLK is reset (step S42), and the fact that the copy has failed and the normal state is displayed is displayed by the operation unit 9 (step S43).

FIG. 11 relates to the third aspect of the present invention. This routine is entered when a polygon rotation abnormality occurs. First, after copying is stopped (step S51),
The polygon CLK is reset (step S52), and it is displayed by the operation unit 9 that copying has failed and that the normal state has been restored (step S53).

[0025]

According to the first aspect of the present invention, when an abnormality occurs in the main scanning counter during copying, the copying operation is automatically restored after the copying is stopped, so that an abnormal image is output and wasteful toner and the like are output. There is no wear.

According to the second aspect of the present invention, if a write CLK error occurs during copying, the copying operation is automatically resumed after the copying is stopped, so that the toner is not wastefully consumed.
Further, since the write CLK is automatically reset, the user does not have to take the trouble of turning on / off the power.

According to the third aspect of the present invention, when a polygon rotation error occurs during copying, the copying operation is automatically resumed after the copying is stopped, so that wasteful toner is not consumed. In addition, since the polygon clock is automatically reset, the user does not have to turn on / off the power supply.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment to which the present invention has been applied.

FIG. 2 is a block diagram illustrating a configuration of a writing unit.

FIG. 3 is a block diagram showing a configuration of a GAVD unit and its periphery.

FIG. 4 is a block diagram illustrating a configuration of an output control unit.

FIG. 5 is a flowchart illustrating a rough operation of the image forming apparatus.

FIG. 6 is a flowchart showing a main scanning counter check operation.

FIG. 7 is a flowchart illustrating a main scanning counter value abnormality detection operation.

FIG. 8 is a timing chart showing a forced lighting timing detection operation.

FIG. 9 is a flowchart showing a forced lighting timing detection operation.

FIG. 10 is a flowchart showing a write CLK abnormality detection operation.

FIG. 11 is a flowchart showing a polygon CLK abnormality detection operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanner part 2 Printer part 3 CPU 9 Operation part 11 VPU 12 IPU 21 GAVD 22 LD control part 23 LD 24 PD 25 Deflector 27 Photosensitive drum 28 Photodetector 30, 38 Clock control part 31, 32 Main scanning counter 33 Secondary Scan counter 34 Main / sub scanning gate signal generation unit 37 LDON / OFF unit 39 Monitoring signal generation unit 40 Abnormality monitoring unit 41, 42 PLL

Claims (3)

[Claims] 1. An image forming apparatus comprising: an abnormality cause identification unit capable of detecting a writing abnormality and identifying the cause of the abnormality; and a main scanning counter for measuring a predetermined main scanning period. An image forming apparatus comprising: a control unit for stopping image formation when a cause specifying unit detects an abnormality of the main scanning counter. 2. An image forming apparatus having an abnormality cause identification unit capable of detecting a write abnormality and identifying the cause of the abnormality, wherein the abnormality cause identification unit detects an abnormality in a write clock during image formation. An image forming apparatus, further comprising control means for stopping image formation, resetting the write clock, and returning to a normal state. 3. An image forming apparatus having an abnormal cause specifying means capable of detecting a writing error and specifying the cause of the error. An image forming apparatus, further comprising control means for stopping the formation, resetting the polygon clock, and returning to a normal state.