JPH0216519B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system for an image forming apparatus such as an electrophotographic printer.

FIG. 1 is a schematic diagram showing the operation of a conventional electrophotographic printer.

In FIG. 1, 1 is a rotating drum with a photosensitive layer on its surface, 2 is a charger for positively charging the photosensitive layer of the rotating drum 1, and 3 is the rotating drum 1 charged by the charger 2. A laser device forms an electrostatic latent image by irradiating a photosensitive layer with a laser beam corresponding to a character pattern generated by a character generation mechanism described later; 4 is an electrostatic latent image on the rotating drum 1 formed by the laser device 3; 5 is a transfer device that transfers the image developed by the developer 4 onto the recording paper of the rotating drum 1; 6 is a fixing device that fixes the image transferred to the recording paper; 7 is the recording paper 8 is a stacker that stores the paper that has been printed by fixing the image; 9 is a stacker that receives print data from an external device such as a host computer using a character code, and stores at least one page worth of print data temporarily. A buffer storage device 10 is a character generation mechanism that extracts print data from the buffer storage device 9 and generates a character pattern corresponding to the print data. In addition, n is the page where the laser device 3 is forming an electrostatic latent image on the rotating drum 1, n-1 is the page that is being developed, n-2 is the page that is being transferred, and n-3 and n-4 are the pages that have completed transfer. and n-5 indicates a page in the process of being fixed.

In such an electrophotographic printer, for example, when the rotation of the rotary drum 1 is stopped, the charger 2 does not uniformly charge the rotary drum 1, and the formation, development, transfer, and formation of an electrostatic latent image occur. Fixing is not performed normally over a certain range in the front and back of the rotating direction of the rotary drum or the running direction of the recording paper.

For this reason, in an electrophotographic printer, after at least one page of print data is transferred from a host computer and stored, the formation of a latent image on that page is started.

However, if a paper jam occurs in the fixing device 6, for example, printing will be interrupted, the paper jam will be removed, and printing will be restarted, but at that time, a number of defective pages will be generated. In such a case, n
- You need to go back and reprint page 5. However, since the buffer storage device 9 does not store the print data of the page on which the latent image has been formed, the n-5
It is necessary to go back to the page and re-transfer the print data for several pages. For this purpose, the host computer must store these print data even after outputting them to the printer. Another problem was that the functions of the host computer and other input/output devices were degraded in order to transfer data.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to avoid adverse effects on the host computer, etc. when reprinting is caused due to paper jams in the recording paper. It is an object of the present invention to provide a control method for an image forming apparatus that does not cause problems.

In order to achieve the above object, the present invention provides a buffer storage device that stores at least print data from a page where a latent image is being formed to a page where a latent image is being fixed, out of print data sent from a host device, and a discharge process after fixing. detecting means for detecting a page located in the buffer storage device, and erasing the fixed page in the buffer storage device in accordance with the output from the detection device, thereby erasing the fixed page from the page on which a latent image is being formed in the buffer storage device. This is achieved by a control system for an image forming apparatus characterized in that images up to the page being fixed are constantly stored.

The gist of the present invention will be specifically explained below using an example shown in FIG.

The figure is a schematic diagram showing the operation of an electrophotographic printer to which the present invention is applied. The same reference numerals indicate the same objects throughout the figures. Reference numeral 11 denotes a multiple-page buffer that receives print data using character codes or the like from an external device such as a host computer, and temporarily stores the print data from the page on which the laser device 3 is forming a latent image to the page on which the fixing device 6 is fixing. storage device, 1
2 is a detector 13 used as means for detecting a page that has finished fixing in the fixing device 6 and is in the process of being ejected;
is a register used as means for storing the page in the process of being ejected. Also n, n-1, n-
2, n-3, n-4 and n-5 are as explained in the conventional example of FIG.

In such a configuration, print data for pages n-5 to n are temporarily stored in the buffer storage device 11 provided corresponding to a plurality of pages. The detector 12 detects the identification code of the page discharged to the stacker 8 after printing is completed by fixing by the fixing device 6, and sends this to the register 13. The register 13 stores the identification code of the page that is ejected to the stacker 8 after printing is completed by fixing by the fixing device 6, and the stored contents are updated by the signal from the detector 12. At the same time, the plural page buffer storage device 11 erases the stored print data of the first page, and receives and stores the print data of a new page from the host computer. In this way, the buffer storage device 11 for a plurality of pages stores at least print data from the page where the latent image is being formed to the page where the latent image is being fixed.

As explained above, according to the present invention, the buffer storage unit includes a plurality of pages and stores print data from the page where the latent image is being formed to the page where the image is being fixed. When a jam etc. occurs, when restarting the device and reprinting after troubleshooting, there is no need to retransmit the print data from an external device such as a host computer during this time. This has the effect of not interfering with the operation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the operation of a conventional electrophotographic printer, and FIG. 2 is a schematic diagram showing the operation of an electrophotographic printer to which the present invention is applied. In these figures, 1 is a rotating drum, 2 is a charger, 3 is a laser device, 4 is a developer, 5 is a transfer device, 6 is a fixing device, 9 is a buffer storage device, 10 is a character generation mechanism, and 11 is a plurality of A page buffer storage device, 12 a detector, and 13 a register.

Claims (1)

[Claims] 1 Among the print data sent from the host device,
A buffer storage device stores print data from at least a page on which a latent image is being formed to a page on which a latent image is being fixed; and a detection means for detecting a page that has finished fixing and is in the process of being ejected; An image forming apparatus characterized in that the fixed page in the buffer storage device is erased, so that the pages from the page on which a latent image is being formed to the page on which the image is being fixed are constantly stored in the buffer storage device. control method.