JPS623562A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that forms an image in accordance with a photoelectrically converted image signal.

[Conventional technology]

FIG. 10 is a control block diagram of a conventional image forming apparatus. Reference numeral 51 denotes a reader, for example, an image sensor 51a composed of a COD, a buffer memory 51b for holding the output of the image sensor 51a, an image processing section 51c, 9 image interperiods. memory 51
d, a control section 51e, and the like.

Reference numeral 52 denotes a printer section, which includes a modulation circuit 52a that modulates the image signal output from the image synchronization memory 51d, and a modulation circuit 5.
It is comprised of a laser modulator 52b, a controller 52c, etc., which converts the modulation signal sent out from 2a into a drive signal for a laser (not shown), that is, an on/off signal.

An optical image is read by an image sensor 51a such as a contact type CCD, and a memory, that is, a buffer memory 51, serially captures the read image data according to instructions from a control unit 51e.
an image synchronization memory 5 for temporarily storing the image in b and further transmitting the read image in synchronization with the scanning drive system of the printer;
1d, are sequentially read from the buffer memory 51b and transmitted to the laser modulation circuit 52 via the modulation circuit 52a of the printer section 52.
It is customary to send an image signal to b and output the image onto a recording medium, such as recording paper.

In this case, if an image is read with a resolution of approximately l 6 dot#+m and a throughput of 20 images per minute is to be achieved, the transfer time for each pixel per dot will be approximately 60 nsec. Image signals having such transfer speeds are sequentially sent to the scanning drive system of the printer via each unit.

[Problem that the invention seeks to solve]

In the apparatus configured as described above, it is necessary to check the communication status of one image signal.

This is because, if noise is superimposed due to an external factor during image signal transfer, especially when converting parallel data to serial data in the buffer memory 51b, an image signal different from the read image may be used to drive the printer's scanning drive. This results in problems such as a blurred image affected by noise being output. For this reason, when the above-mentioned symptoms appeared in the image, a measurement device such as an oscilloscope was connected to the main body of the device and the input/output of the image signal was monitored to diagnose each unit. As mentioned above, the transfer time per dot of the image signal is about 60 nsec, and the image signal is uncertain, so there are problems such as the inability to accurately diagnose each unit. was there.

[Means for solving problems]

The image forming apparatus according to the present invention includes a test pattern sending unit that sends out a predetermined test pattern in synchronization with the writing of an image signal into a buffer, and compares the test pattern read from the buffer with a reference test pattern to detect transmission errors. The apparatus is provided with a counting means for counting the number of transmission errors, and a signal control means for controlling transmission of the image signal according to the number of transmission errors counted by the counting means.

[Effect]

In this invention, the random test pattern generated by the test pattern sending means is written into the buffer in synchronization with the image signal, and the counting means counts the discrepancies between the test pattern read from the buffer and the reference test pattern. A signal control means counts transmission errors of test patterns between units, and controls transmission of image signals according to the counted value. At that time, the degree of occurrence of transmission errors and the system status can be displayed if necessary.

〔Example〕

FIG. 1 is a configuration block diagram of an image forming apparatus showing an embodiment of the present invention, in which 1 is a contact type photoelectric element, which sends analog signals V1 to V5 output from channels 1a to 1e to a signal processing section 2. do. The signal processing section 2 samples and holds the analog signal, and sends the analog signal for 5 channels to the A/D of the image reading control section 4 via the communication cable 3.
It is transferred to the D converter 4a. 4b is a link memory serving as a buffer, which arranges the A/D converted image signals. 4
c is an image processing unit (IPU) that multi-values the image signal and converts it into a signal expressing halftones. It also processes color image signals, for example image signal processing such as gamma conversion. 4d is a synchronous memory that sends the image signal from the IPU 4c to the printer 5. 4e is a synchronous control circuit that controls Ilo between the signal processing section 2 and the connection memory 4b in accordance with commands from the control section 4h. 4f is a synchronization control circuit that controls writing of the image signal read from the connection memory 4b to the IPU 4c. 4g is a synchronous control circuit, I PU
The writing of the image signal read from 4c into the synchronous memory 4d is controlled. In addition, when 1 to 4 are collectively referred to as beams.

The printer 5 includes a page memory 5a that stores page units sent from the synchronous memory 4d, a modulation circuit 5b that modulates the image signal stored in the page memory 5a,
A laser modulator 5c that converts the modulation signal sent from the modulation circuit 5b into a laser drive signal (not shown), that is, a blinking signal, and a BD sensor 5 that detects the laser scanning start position.
d, a synchronous control circuit 5e, a control section 5f, etc. 6 is an I10 port, which is connected to the league control unit 4h. 7 is an I10 port, which is connected to the control section 5f of the printer 5. Note that the control unit 5f determines an image data transmission error in the page memory 5a, and
As long as the number of transmission errors is less than the arbitrarily set number of transmission errors, the image data is repeatedly transferred to the page memory 5a.

FIG. 2 is a configuration block diagram showing details of the link memory 4b shown in FIG. 1, and 11.12 is a /< switch IC,
An inverter 13 is connected between the bus switching ICs 11 and 12. 14.15 is a buffer memory, and inverter 16.15 is a buffer memory. Multiplexers 17 and 18 switch the read/write address of the image signal. 19 is a multiplexer,
Channel select terminal C of buffer memory 14.15
Switch 8. 20 is a gate circuit that extracts only the test pattern portion of the output data. 21 is a gate circuit that extracts only the reference pattern. A comparator 22 compares the test pattern output from the buffer memory 14.15 with the reference pattern and extracts a signal that does not match, that is, a part of the error. Reference numeral 23 denotes an error counter serving as a counting means of the present invention, which counts a portion of errors output from the comparator 22. 24 is a latch circuit that outputs the count value of the error counter 23 to the VSYNC signal (
(described later) is held at the falling edge. 25 is a gate circuit to which a test pattern is added.

26 is a gate circuit that removes the test pattern. 27
28 is an inverter circuit, and 28 is a ROM that stores unaligned random data, such as "01011j, li'
A test pattern having a plurality of o1100J is written in a small capacity. 29 is a ROM in which a reference pattern is written in the same way as a test pattern. In addition, ROM2
The random data written in 8.29 is the same.

Reference numeral 30 denotes a timing circuit which constitutes a test pattern sending means of the present invention, which controls the sending of random data written in the ROM 28 and inserts it into an interval other than the image signal interval in synchronization with the horizontal synchronizing signal (BD double signal). 31 is a counter that inputs the sub-scanning direction address of the test pattern in synchronization with the VSYNC signal.

Runt. 32 and 33 are timing circuits that control the image effective area. A write counter 34 counts write addresses of the buffer memories 14 and 15 via a bus 37. A counter 36 counts read addresses of the buffer memory 14 and 15 via the bus 35.

Reference numeral 38 denotes an access controller, and buffer memory 14.
Controls access to 15. Reference numeral 39 denotes a main control unit serving as a signal control means of the present invention, which determines the transmission error state based on the preset number of error occurrences based on the count value input via the I10 port 6, and instructs retransmission of the test pattern. At the same time, the transmission quality is displayed on the display means of the operation section (not shown). Further, the state of the transmission error is determined based on a preset number of occurrences of the error, the possibility of recurrence is determined, and transmission of the image signal is suppressed, and a display means displays a message to that effect. Reference numeral 40 denotes an OR gate circuit, which sends image signals for five channels inputted to the connecting memory 4 to the printer 5. Note that the connection memory 4b is configured in the same way for each channel, but for the sake of explanation,
Only the channel 1a is shown.

Next, the operation in FIG. 2 will be explained with reference to FIGS. 3(a) to 3(C) and FIGS. 4(a) to (h).

Figures 3(a) to (C) show the buffer memory 1 shown in Figure 2.
4.15 is a time chart showing the relationship between the image signal and the test pattern written in FIG.

In FIG. 3(a), BD indicates the horizontal synchronizing signal sent from the BD sensor 5c, and in FIG. 3(b), VI
DEO shows image signals for 5 channels, as shown in the same figure (C).
, TP is a test pattern and indicates the first line test pattern written in the ROM 28.

FIGS. 4(a) to (h) show the buffer memory 1 shown in FIG.
4.15 is a time chart showing the relationship between the image signal read out and the test pattern.

In FIG. 3A, CK is a read clock and is input to the read counter 36. In the same figure (b), C
H, is read data, and test patterns TP are added to both sides of the image signal Vt. In (b) to (f) of the figure, CH2 and CH5 are read data, and test patterns TP are added to both sides of each image signal v2 to v5, respectively. In FIG. 4(g), RV is extracted image data and is sent to the IPU 4c. Extracted image data R
Test patterns are added to both sides of V. The same figure (h
), MV is valid image data and is stored in the synchronous memory 4d.
will be sent to.

The horizontal synchronizing signal BD shown in FIG.
e, the test pattern written in the ROM 28 is displayed on both sides of the section of the analog signals Vl to 5 which are output from the channels 1a to 1e of the contact type photoelectric element 1 in synchronization with the water synchronization signal BD. Among them, random data of the l-th line is added and stored in the buffer memories 14 and 15 in parallel. This operation is performed on the input image signal in synchronization with the horizontal synchronization signal BD. At this time, the test pattern TP is sequentially added with random data from the ROM 28 to the corresponding image signal and stored in the buffer memory 74.15.

Next, in synchronization with the read clock CK input to the read counter 36 (see FIG. 4(a)), the signals are read from the buffer memory 14.
Read data CH+ CHs corresponding to e (4th
(see Figures (b) to (f)) are input to the comparator 22 via the bus switching IC 12 and the gate circuit 2o. On the other hand, the reference pattern read out from the ROM 29 is simultaneously input to the comparator 22 via the gate circuit 29 . Reading of this reference pattern is controlled by the timing circuit 32, and the comparator 22 compares the test pattern TP, which is the same random data.

If this comparison shows that the test patterns do not match,
A predetermined pulse signal is output from the converter 22.

The error counter 23 counts this pulse signal, and the VSYNC signal (fifth
(see figure), the count value of the error counter 23 is held in the latch circuit 24. This latch output is I1
If the transmission error in one image is larger than a predetermined setting value, it is determined by the main control unit 39 via the 0 port 6 that the transmission of the same image data is repeated and the memory 4
Command b. If the same transmission error is repeated a predetermined number of times, it is determined that the transmission error cannot be recovered, and the system is displayed on the display means of the operation section (not shown) to warn the operator and stop the system. Note that if the transmission error falls within the permissible range, sending out the image data is continued. This is to allow image formation to be executed without stopping the system in the case of a transmission error that does not cause any problem in the output image, so as not to reduce operational efficiency.

Note that transmission error monitoring is limited to the effective image area (indicated by diagonal lines) shown in FIG. 6, and error counting is not performed for unnecessary areas. Further, in FIG. 6, vl indicates the sub-scanning range of the effective image area, V2 indicates the maximum sub-scanning range, Hl indicates the main-scanning range of the effective image area, and H2 indicates the maximum main-scanning range. .

Next, the system diagnosis control operation of the present invention will be explained with reference to FIG.

FIG. 7 is a flowchart illustrating a system diagnosis control operation of an image forming apparatus according to an embodiment of the present invention. Note that (1) to (9) indicate each step.

First, wait for the copy-on determination routine to finish.1)
, A test pattern sending routine for adding the test pattern written in the ROM 28 to both sides of the section of the analog signal 1 to v5 and writing it in the buffer memory 14.15 is executed prior to the main image forming operation 2), the read clock CK The test pattern TP is read out from the buffer memory 14.15 in synchronization with the error counter 23.
It compares it with the reference pattern written in the CM 29 and counts transmission errors. Next, after a predetermined period of time has elapsed, the main control unit 39 reads out the number of transmission errors held in the latch circuit 24 (3), and checks whether the transmission errors on that transmission path are within a preset tolerance range. If the judgment is YES (4), the normal copy operation is executed (5). At this time, test patterns TP are placed on both sides of the read data CHI to CH5 in the buffer memories 14 and 15.
Next, in parallel with writing the read data CI (+"CR2 to the synchronous memory 4d), check whether the same transmission error as described above is within the preset tolerance range. Judging (6
). If this judgment is YES, return to step (1),
If No, it is determined whether the transmission error has occurred more than a preset number of times (7). If No, the process returns to step (5), and if YES, the process proceeds to step (9).

On the other hand, in step (4), it is determined whether transmission errors have occurred more than a preset number of times.
), if NO, the process returns to step (2), and if YES, it is determined that there is no hope of recovery from the transmission error on the display means (not shown), and the main control unit 39 displays a warning and stops the system (9).

Next, with reference to FIG. 8, the interaction between the league section and printer 5 shown in FIG. 1 will be explained.

FIG. 8 is a flowchart illustrating the mutual operation of the league section and printer 5 shown in FIG. In addition, (1) to (8
) indicates each step.

The printer 5 first executes a communication routine to communicate image data from the league section 1), determines whether a print signal has been sent from the league section 2), and if No, stores the image data in a RAM (not shown); If YES, perform a transfer routine to start transferring image data (3)
. Next, it is determined whether the image data transmission error is within a preset tolerance range 4)
, if YES, execute the normal copy operation and step (1)
), return to (5), and if NO, determine whether transmission errors have occurred more than a preset number of times (Ei),
If YES, it is determined that the league communication routine has failed, a warning to that effect is displayed on the display means, a failure sequence is performed to stop the system, and the control is terminated (7). On the other hand, if it is determined in step (6) that the number of transmission errors is less than the preset number, the transmission error count is increased (8) and a request is made again to transfer the image data from the reader section to the page memory 5a. Return to step (2) and check for transmission errors.

Although the case of a color image signal is not explained in detail in the above embodiment, if a color separation filter is provided in the contact type photoelectric element 1 and the signal is converted into an RGB signal, transmission errors can be similarly checked.

FIG. 9 is a sectional view showing an embodiment of the image forming apparatus according to the present invention, in which 41 is a document, 42 is a reader section, a platen glass 42a on which the document 41 is placed, and a platen glass 42a on which the document 41 is placed;
A light source 42b that illuminates the original 41, a reflecting mirror 42c that focuses the light from the light source 42b, a light converging lens 42d that focuses the light from the light source 42b onto the original 41, and a close-contact type that converts the focused optical image into an electrical signal. A photoelectric conversion element 42e, a signal processing circuit 42f that shapes the waveform of the signal output from the contact type photoelectric conversion element 42e, a transmission cable 42g that transmits the signal output from the signal processing circuit 42f, and a signal processing circuit 42f.
It is composed of an image reading control section 42h that processes signals output from the image reading control section 42h and controls each section.
The scanning table 4S connected to the wire 44 reciprocates in the direction of the arrow in accordance with the rotation of the pulley 45. A motor 46 drives the pulley 45.

Reference numeral 47 denotes a printer section, which includes an interface circuit 47a for communicating signals output from the reader section 42, a laser modulation section 47b for converting the signals output from the interface circuit 47a into laser light, and a scanner section for scanning the laser light. 47c, a polygon mirror 47d that changes the direction of the scanned laser beam;

A photosensitive drum 47e that forms a latent image using laser light, a charger 47f that charges the photosensitive drum 47e, a developer 47g that develops the latent image on the photosensitive drum 47e, and a toner (developing material) supplied to the developer 47e. Toner hopper 4
7h, a cassette 4'7i that stores the recording paper, a paper feed roller 47j, a registration roller 47k that aligns the leading edge of nine images, a transfer charger 471 that transfers the toner image onto the recording paper. ) a conveying unit 47m that conveys the recording paper onto which the toner has been transferred; a fixing unit 4 that fixes the transferred toner image and the recording paper;
7n, a paper output tray 47o on which the fixed recording paper is placed;
, BD sensor 47p, etc.

Note that since the single image forming operation is based on a known electrophotographic method, detailed explanation will be omitted.

〔Effect of the invention〕

As explained above, the present invention includes a test pattern sending unit that sends out a predetermined test pattern in synchronization with the writing of an image signal into a buffer, and compares the test pattern read out from the buffer with a reference test pattern to detect transmission errors. Since the count means for counting the number of transmission errors counted by the count means and the signal control means for controlling the transmission of the image signal according to the number of transmission errors counted by the counting means are provided, the transmission check of the image data for the valid image area can be performed by transmitting the image signal. This can be done quickly and accurately before and during transmission, and the transmission error status of each unit can be displayed if necessary. In addition, since retransmission or stop of image signals is controlled according to transmission errors, system diagnosis can be easily performed, and
Since system failures can be predicted, system reliability can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing details of the connection memory shown in FIG. 1, and FIGS. A time chart showing the relationship between the image signal and the test pattern written in the connection memory shown in FIG. 2, and FIGS. 4(a) to (4).
h) is a time chart showing the relationship between the image signal read out from the connection memory shown in FIG. 2 and the test pattern;
FIG. 5 is a time chart illustrating the VSYNC signal that determines the effective image area, FIG. 6 is a schematic diagram illustrating the effective image area, and FIG. 7 is a system diagnostic control of an image forming apparatus showing an embodiment of the present invention. A flowchart explaining the operation,
FIG. 8 is a flowchart explaining the interaction between the reader section and printer shown in FIG. 1, FIG. 9 is a sectional view showing an embodiment of the image forming apparatus according to the present invention, and FIG. It is a control block diagram. In the figure, 1 is a contact type photoelectric element, 2 is a signal processing unit, 3 is a communication cable, 4 is an image reading control unit, 4a is an A/D converter, 4b is a connection memory, 4c is an image processing unit, 4
d is a synchronous memory, 4e to 4g are synchronous control circuits, 4h is a control unit, 5 is a printer, 5a is a page memory, 5b is a modulation circuit, 5c is a laser modulation unit, 5d is a BD sensor, 5e is a synchronous control circuit, 5f is the control unit, 11.12 is the bus switching I
C113 is an inverter, 14.15 is a buffer memory,
16 is an inverter, 17 to 19 are multiplexers, 20
, 21 is a gate circuit, 22 is an inverter, 23 is an error counter, 24 is a latch circuit, 28.29 is a ROM
, 3o is a timing circuit, and 39 is a main control section. 3rd cause Figure 4 (h) MV VI V2 V3 V4 V5 5th
Figure 6 Figure 7 Figure 8

Claims (4)

[Claims] (1) It has a buffer that converts an image signal to be photoelectrically converted into serial data, writes the image signal from this buffer to a synchronizing means in predetermined units, and converts an image according to the image signal read out from the synchronizing means. In the image forming apparatus for forming an image, a test pattern sending means for sending out a predetermined test pattern in synchronization with writing of the image signal to the buffer, and comparing the test pattern read from the buffer with a reference test pattern, An image forming apparatus comprising: a counting means for counting transmission errors; and a signal control means for controlling transmission of the image signal according to the number of transmission errors counted by the counting means. (2) The image forming apparatus according to claim (1), wherein the test pattern is a random pattern. (3) The image forming apparatus according to claim 1, wherein the counting means counts transmission errors before and during transmission of the image signal, and displays the counted transmission errors. (4) The number of transmission errors of the image signal sent from the synchronous memory is counted, and the transmission of the image signal is repeated until the error count exceeds an arbitrarily set number of errors. The image forming apparatus according to scope (1).