JPH0336071A - Erroneous printing detection apparatus - Google Patents

Abstract

PURPOSE:To realize a printing apparatus capable of detecting erroneous printing and having high reliability from the aspect of the ensurance of printing data by providing a bit map memory storing printing data and also providing a data reader for reading the result printed on paper, the control circuit thereof, a phase difference control circuit and a comparing control circuit. CONSTITUTION:A phase difference control part 7 takes in printing data simultaneously with printing operation and stores the same in a bit map memory 2(BM2)8. The phase difference control part starts the reading of the printing data from the BM2 8 at a time when the first data appears at a printing result reading position B after printing to send the same to a comparing control part 9. In synchronous relation to this operation, a printing data reading control part 17 starts the reading of data from a sensor 10 and reads data from a reading dot line buffer 12 by data comparing start indication to send the same to the comparing control part 9. The comparing control part 9 performs comparison at every one dot and informs an alarm to a control part at the time of non-coincidence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for print data processing in a printing device.

[Conventional technology]

Conventionally, printing apparatuses do not have a means for checking whether print data is correctly printed on printing paper in the print data processing control section of the printing apparatus, and there is a possibility that the print data may be printed out incorrectly. Even with conventional printing devices, parity is added to the memory that stores print data in order to guarantee the print data as much as possible, and parity is checked, and impact printers print whether or not the driver that drives the hammer is driven. Efforts are being made to ensure the print data is correct until just before it is printed on printing paper, such as by comparing it with the print data.

[Problem to be solved by the invention]

However, even if the driver circuit that drives the hammer has been checked, it has not been possible to check whether the driven hammer hit the type drum or type belt, so there may be cases where part of the hammer is broken. , the digit will be missing, but an alarm will not be reported and the printout will continue to be erroneously printed. Regarding electrophotographic non-impact printers, if the photosensitive drum is scratched, characters may not be printed correctly in that area, or paper or other material may become jammed in the area where the laser beam hits, blocking the laser beam from hitting the photosensitive drum. However, if the latent image on the photosensitive drum is not transferred to the paper because the transfer section is clogged with paper or the like, there is a drawback that the printout will be erroneously printed.

[Means to solve the problem]

The present invention has a bitmap memory for storing print data, a data reader for reading the results printed on paper, a control circuit thereof, a phase difference control circuit, and a comparison control circuit. To provide a very reliable printing device that enables printing error detection by comparing with data and guarantees print data.

That is, the present invention provides a bitmap memory for storing print data, a data reader for reading print results, a control circuit thereof, a phase difference control circuit for correcting and controlling the time difference from the print position to the data reader, and print data and print results. It mainly consists of a comparison control circuit that compares read data.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic block diagram of the erroneous printing detection method of the present invention.
FIG. 2 shows a schematic structural diagram of an electrophotographic non-impact printer.

Print data sent from a host device is received by a control unit 1 and stored in a code page buffer (CPB) 2. When one page worth of print data is stored in the CPB 2, the control section 1 drives the dot expansion control section 4 and also drives the mechanical control section 3 for preparation. The driven dot expansion control unit 4 extracts a character code from the CPB 2, reads out a character pattern corresponding to the character code from a character generator memory (CG) 5, and stores it in a bitmap memory I which is a print data dot expansion memory.
(BMl) Expand 6 heads. Repeat the same process,
EMI one page worth of print data stored in CPB2
6, the dot development control section 4 activates the mechanical control section 3 and the phase difference control section 7. followed by BMI
The print data expanded into dots is read out from 6, and the read data is placed on the dot data bus to the mechanical control section 3 and phase difference control section 7. When activated by the dot development control section 4, the mechanical control section 3 reads the data in synchronization with a dot-by-dot signal from the dot data bus that causes the laser beam 15 to turn ○N10FF.
is controlled according to print data to draw a latent image on the photosensitive drum 17. This latent image is developed by a developing device 16 and placed on a sheet of paper 20.
is transferred to the fixing section 18, and is fixed by the ejection roller 19.
is discharged to the stacker section.

At the same time as this printing operation, the phase difference control section 7 activated by the dot expansion control section 4 takes in print data from the dot data bus and stores the taken in print data in the bitmap memory 2 (BM2) 8. After the first data of one page is printed as a latent image at the print position A on the photosensitive drum 17, the phase difference control unit starts reading the print data from the BM28 at the time when the print result appears at the print result reading position B. The read data is sent to the comparison control section 9.

In synchronization with this, the print data reading control unit 11 starts reading from the sensor 10, stores the read data in the reading dot line buffer 12, and in response to a data comparison start instruction, reads out the data from the reading dot line buffer 12 and controls the comparison. Send data to section 9. Comparison control unit 9 compares dots dot by dot, performs corrections and comparisons in units of one dot line or several dot lines, and recompares each dot. If the result is a discrepancy, an alarm is reported to the control unit. do. The reading control unit 11 controls the light amount of the light source 13 to ensure reading, and controls the reading level of the reading sensor 10, especially since the electrophotographic method requires a back.

Recently, image data and graphic data are printed out using printing devices, but according to this method, it is possible to check the printing results of these image and graphic data.

That is, if the image/figure processing unit 21 is connected as shown in FIG. The data is developed in the bitmap memory 3 (BM3) 23 of the dot development memory. When one page's worth of data has been developed on the BM3 23, the image/figure control unit 22 reads the data from the BM3 23 onto the dot data bus in synchronization with a dot-by-dot signal that turns the laser beam 0N10FF. At this time, if there is character data, the character data is also transferred to the dot bus via Wi-Fi.
Red-ORed. Therefore, since the print data used for checking is stored in the BM 28 in a form in which image data, graphic data, and character data are all ORed together, it is possible to check the print results of any data in this method.

The reason why this method of detecting printing errors has become possible is that the density of memory elements has become much higher and the cost has decreased, and the COD technology of the reading sensor has improved. by.

〔Effect of the invention〕

As described above, the present invention has the effect of being able to detect printing errors and greatly increasing the reliability of printing guarantees.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention, and FIG. 2 is a schematic structural diagram of an electrophotographic printing apparatus. 1...Control unit (controls data transfer with the host device and controls the entire printer), 2...CP
B (code page buffer), 3... Mechanical control unit, 4... Dot development control unit that develops character data into dots, 5... Character pattern memo')
(CG), 6...Bitmap memory l (character data dot expansion memory), 7...Phase difference control unit (time difference control between print position and print data reading position), 8... ... Bit map memory 2 (print data storage memory for detecting printing errors), 9 ... Comparison control section, 10 ... Sensor (for reading print data), 11 ... ...reading control unit, 12... river/reading dot line buffer, 13... light source (
(for reading sensor), 14...Laser control unit, 15...Laser beam, 16...Developer, 17...Photosensitive drum, 189.・・・・
Fixing section, 19... Ejection roller, 2o...
・Paper, 21... Image/graphic processing section, 22
...Image/figure data control section, 23...
...Dot expansion memory for image/figure data (bitmap memory 3).

Claims (1)

[Claims] A data reader and its control circuit for reading the print result printed on paper, a bitmap memory for storing the print data in dot expanded form, and a control circuit for controlling the time difference from the print position to the data reader position. An erroneous printing detection method comprising: a phase difference control circuit; and a comparison control circuit that compares print data with read data of a print result.