JPS623560A - Image forming device - Google Patents

Abstract

PURPOSE:To attain quick and accurate transmission check of image data at fast transmission speed by sending a prescribed test pattern synchronously with the write of an image signal intoa buffer, comparing the pattern with a reference test pattern with a reference test pattern and deciding the transmission error. CONSTITUTION:The test pattern sending routine writing a test pattern written on a ROM 28 to buffer memories 14, 15 is executed prior to main image forming operation, the test pattern is read from the buffer memories 14, 15 synchronously with a read clock CK, an error counter 23 compares the pattern with a reference pattern written on a ROM 29 to count transmission errors. Whether or not the transmission errors are within a preset permissible range is judged, and when it is YES, the normal copying is executed. If NO, it is judged that there is no possibility of transmission error recovery, a main control section 39 displays an alarm on a display means to stop the system.

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, in which 51 is a reader, an image sensor 51a composed of, for example, a COD, a buffer memory 51b that holds the output of the image sensor 51a, 2 image processing units 51c, 2 image synchronization memory 5] 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 52.
It is comprised of a laser modulator 52b, a controller 52c, etc., which converts the modulation signal sent from the output terminal a 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.
11, and then sequentially read out from the buffer memory 51b to the image synchronization memory 5Td for sending out the read image in synchronization with the scanning drive system of the printer, and then read out sequentially from the buffer memory 51b to the laser modulation circuit 5 via the modulation circuit 52a of the printer section 52.
It is customary to send an image signal to 2b and output the image onto a recording medium, such as recording paper.

In this case, if an image is read with a resolution unit of about 16 dots/mm and a throughput of 20 images per minute is to be achieved, the pixel transfer time per 1 dot is:

It is roughly estimated to be around 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 state of the 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 1 dot of the image signal is about 60 n5ec, and the image signal is uncertain, so there are problems such as the inability to accurately diagnose each unit. There was a point.

[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 writing of an image signal into a buffer, and compares the test pattern read from the buffer with a reference test pattern and transmits the test pattern. A signal determining means for determining an error is provided.

[Effect]

In this invention, a random test pattern generated by a test pattern sending means is written into a buffer in synchronization with an image signal, and a signal determining means compares the test pattern read from the buffer with a reference test pattern, and transmits the test pattern. Determine the error.

〔Example〕

FIG. 1 is a block diagram of the structure of an image forming apparatus showing an embodiment of the present invention. Reference numeral 1 denotes a contact type photoelectric element, which converts analog signals (1) to (5) output from channels 1a to 1e into a signal processing unit 2. Send to. 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) which multivalues the image signal and converts it into a signal expressing halftones, and also performs image signal processing such as color 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 the signal processing section 2 and the connecting memory 4 according to commands from the control section 4h.
Control Ilo with b. 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 PU4
The writing of the image signal read from c to the synchronous memory 4d is controlled. Note that 1 to 4 are collectively referred to as a leader.

The printer 5 includes a modulation circuit 5a that modulates the image signal sent out from the synchronous memory 4d, a laser modulation section 5b that converts the modulation signal sent out from the modulation circuit 5a into a drive signal for a laser (not shown), that is, a blinking signal, BD sensor 5c that detects the scanning start position, synchronous control circuit 5
d, a control section 58, etc. 6 is an I10 port, which is connected to the control section 4h of the reader. 7 is I
10 ports, and is connected to the control unit 5e of the printer 5.

FIG. 2 is a block diagram showing the details of the connection memory 4b shown in FIG. 1. Reference numeral 11.12 is a bus switching IC, and an inverter 13 is connected between the bus switching ICs 11 and 12. 14.15 is a buffer memory, and inverter 1
6. Multiplexers 17 and 18 switch the read/write address of the image signal. A multiplexer 19 switches channel select terminals CS of buffer memories 14 and 15. 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 outputted from the buffer memories 14 and 15 with a reference pattern, and extracts a signal that does not match, that is, a part of the error. An error counter 23 counts a portion of errors output from the comparator 22.

A latch circuit 24 holds the count value of the error counter 23 at the falling edge of a VSYNC signal (described later).

25 is a gate circuit to which a test pattern is added. 26
is a gate circuit that removes the test pattern. 27 is an inverter circuit, 28 is a ROM, and unsorted random data, e.g. 4f rollJ, r
OllooJ 7f (Multiple test patterns are written in a small capacity. 29 is a ROM, and a reference pattern is written in the same way as the test pattern.
The random data written to OM28.29 is the same. Reference numeral 30 denotes a timing circuit which constitutes the test pattern sending means of the present invention, which controls the sending of random data written in the ROM 28, and inserts it into sections other than the image signal section in synchronization with the horizontal synchronizing signal (BD double signal). 31
is a counter that counts the sub-scanning direction addresses of the test pattern in synchronization with the vSYNC signal. 32 and 33 are timing circuits that control the image effective area. 34 is a write counter, which is connected to the buffer memory 14 via a bus 37.
．． Count 15 write addresses. 36 is a read counter, which is connected to the buffer memory 14 through a path 35.
Count 15 read addresses. An access controller 38 controls access to the buffer memories T4 and 7.5. Reference numeral 39 denotes a main control unit which constitutes the signal judgment means of the present invention, which judges the transmission error state from the preset number of error occurrences based on the count value input through the I10 port 6, and instructs to retransmit 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. Although the link memory 4b is configured in the same manner for each channel, only the channel 1a is shown for the sake of explanation.

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 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
HI is read data, and test patterns TP are added to both sides of the image signal (1). Figures (b) to (f)
, 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. Test patterns are added to both sides of the extracted image data RV. Same figure (
In h), MV is valid image data and is stored in the synchronous memory 4.
d.

The horizontal synchronizing signal BD shown in FIG.
When input to e, the test pattern written in the ROM 28 is displayed on both sides of the interval of analog signals 1 to v5, which are output from channels 1a to 1e of the contact type photoelectric element 1 in synchronization with this horizontal synchronizing signal BD. Among them, the first line of random data is added and stored in parallel in the buffer memories 14 and 15. 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 stored in the buffer memory 14, 15 with different random data sequentially added to the corresponding image signal from the ROM 28.

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 FIGS. (b) to (f)) are input to the converter multiplier 22 via the path switching IC 12 and the gate circuit 20. 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 comparator 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 this fact is displayed on the display means of the operation unit (not shown) to warn the operator and the system is stopped. 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. In addition, in FIG. 6, vl indicates the sub-scanning range of the effective image area, ■2 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. There is.

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 that adds the test pattern written in the ROM 28 to both sides of the interval of the analog signals V1 to V5 and writes it in the buffer memory 14.15 is executed prior to the main image forming operation 2). In synchronization, the test pattern TP is read from the buffer memory 14.15, and the error counter 23 is set to R.
It compares with the reference pattern written in OM29 and counts transmission errors. Next, after a predetermined period of time has elapsed, the main control unit 39 reads the number of transmission errors held in the latch circuit 24 (3) and determines whether the transmission errors on that transmission path are within a preset tolerance range. 4), if YES, perform normal copy operation (
5). At this time, the read data CHI to CH5 are stored in the buffer memories 14 and 15 with test patterns TP added to both sides. Next, in parallel with writing the read data CHI''CR2 to the synchronous memory 4d, it is determined whether the same transmission error as described above is within the set tolerance range (6).

If this judgment is YES, return to step (1), and if NO
If so, it is necessary to judge whether the transmission error has occurred more than a preset number of times (7), and if No, step (
Return to step 5), and if YES, proceed to step (9).

On the other hand, in step (4), it is determined whether transmission errors have occurred more than a preset number of times8).
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 for communicating image data from the league club (1), then determines whether a print signal has been sent from the league club (2), and if No, stores the image data in a RAM (not shown). , if YES, performs a transfer routine to start transferring image data (3
). Next, it is determined whether the image data transmission error is within a preset tolerance sieve 7 (4), and if YES, the normal copying operation is executed and the process returns to step (1) (5), and if No, the process returns to step (1) (5). Determine whether transmission errors have occurred more than a preset number of times6)
, If YES, it is determined that the league communication routine is malfunctioning.
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 to transfer the image data from the league again, and step (2) is performed. Return to and perform a transmission error check.

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 league part, a platen glass 42a on which the document 4 is placed, and a light source that illuminates the document 41. 42b, a reflecting mirror 42C for condensing the light from the light source 42b, a light converging lens 42d for condensing the light from the light source 42b on the original 41, and a contact type photoelectric conversion element 42e for converting the condensed optical image into an electrical signal. , a signal processing circuit 42f that shapes the waveform of the signal output from the contact photoelectric conversion element 42e, a transmission cable 42g that sends out the signal output from the signal processing circuit 42f, and a signal processing circuit 42.
It is composed of an image reading control section 42h that processes signals output from f and controls each section, and a scanning table 43 connected to a wire 44 reciprocates in the direction of the arrow according to the rotation of a pulley 45. . 46 is a motor,
Drive pulley 45.

47 is a printer section, which includes an interface circuit 47a that communicates the signal output from the league section 42, a laser modulation section 47b that converts the signal output from the interface circuit 47a into a laser beam, a scanner section 47c that scans the laser beam, A polygon mirror 47d that changes the direction of the scanned laser beam, a photosensitive drum 47e that forms a latent image with the laser beam, a charger 47f that charges the photosensitive drum 47e, and a developer 47g that develops the latent image on the photosensitive drum 47e. , a toner hopper 47h that supplies toner (developing material) to the developing device 47g, a cassette that stores recording paper)
47i, a paper feed roller 47j, a registration roller 47k for aligning the leading edge of two images, and a transfer charger 471 for transferring a toner image onto recording paper. A transport unit 47m that transports the recording paper to which the toner has been transferred, a fixing unit 47n that fixes the transferred toner image and the recording paper, a paper discharge tray 47o that places the fixed recording paper, and a BD. It is composed of a sensor 47P and the like.

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

〔Effect of the invention〕

As explained above, the present invention includes test pattern sending means for sending out a predetermined test pattern in synchronization with writing of an image signal into a buffer, and comparing the test pattern read out from the buffer with a reference test pattern to determine whether the image signal is being transmitted. Since the reliability determination stage f for determining an error is provided, the transmission check of image data having a high transfer rate can be performed quickly and accurately. Further, since it is possible to diagnose each unit in accordance with the transmission error determined by the signal determining means and predict failure of the unit, there is an advantage that inspection and maintenance can be greatly simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of an image forming bag m showing an embodiment of the present invention, FIG. 2 is a block diagram of the configuration of the link memory shown in FIG. 1, and FIGS. 3(a) to (C) are time charts 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 section, 3 is a communication cable, 4 is an image reading control section, 4a is A, /
D converter, 4b is a connection memory, -4c is an image processing unit, 4d is a synchronous memory, 48 to 4g are synchronous control circuits,
4h is a control unit, 5 is a printer, 5a is a modulation circuit, 5b is a laser modulation unit, 5C is a BD sensor, 5d is a synchronous control circuit, 5e is a control unit, 11.12 is a bus switching IC 113 is an inverter, 14.15 is an inverter. Buffer memory, 16 is an inverter, 17 to 19 are multiplexers, 20 and 21 are gate circuits, 22 is a comparator, 23 is an error counter, 24 is a latch circuit, 28.29 is a ROM, 30 is a timing circuit, 39 is a main control section It is. Figure 3 Figure 4 (h) MvT■1v2■3v4■5 Figure 5Figure 6Figure 7Figure 8

Claims (2)

[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 signal determining means for determining a transmission error. (2) The image forming apparatus according to claim (1), wherein the test pattern is a random pattern.