JPH08248855A - Digital image forming device - Google Patents

Abstract

PURPOSE: To write an image again with an optional timing even when a paper feeding timing is delayed. CONSTITUTION: Image data is fetched in a page memory simultaneously when scanning of an original is started (S1) and writing of the image is performed on a paper sheet (S2). Originally, a timing (T3) for switching a register gate on immediately after the paper sheet passes a register sensor (S3) is determined and the paper sheet is stopped when this reaches the register gate before passing T3 (S4). Meanwhile, arrival of the paper sheet on the register gate is determined when this passes T3 (S5), and in the case of Yes, the register gate is opened and the paper sheet is fed to a photosensitive body (S6). In the case of No, writing of the image is stopped (S7). In this case, the arrival of the paper sheet on the register sensor is determined (S8), and in the case of Yes writing of the image is started again (S2) and paper sheets reaching the register gate are left. The paper sheets left after T3 from rewiring are issued and the tips of these are aligned with the written image.

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 such as a digital copying machine or a printer having a page memory, and particularly when the paper feeding timing is delayed, the paper is re-aligned with the image writing timing with respect to the paper. The present invention relates to a device for performing registration control for sending to a photoconductor.

[0002]

2. Description of the Related Art Conventionally, the image forming apparatus shown in FIG. 1 has a tacking point (or a contact point (C.
P. )) And the paper 4 fed from the paper tray 3 to the image writing timing in alignment with the image writing timing. Comparing the distance from the ration gate (hereinafter referred to as the registration gate) to the tacking point, the former is larger than the latter. In such an image forming apparatus, when the feed motor is turned on and the feed clutch is turned on as shown in FIG.
The sheet 4 is fed from the sheet, the writing of the image is started before the sheet arrives at the registration gate 5, and the sheet is fed at the registration position (hereinafter referred to as the registration registration position) on the photoconductor with the written image. The paper feed timing (T3) is set so that the leading edge of the image matches. That is, the sensor (SNR) 1 detects that the paper is fed from the paper tray, and the writing of the image is started after T1.
When the fed paper arrives at the registration gate within a predetermined time (T3), the paper is sent out with the leading edge of the image aligned. Then, the written image is transferred onto the sheet at the tacking point (CP).

[0003]

By the way, in an image forming apparatus such as a light lens type copying machine or a digital copying machine which does not have a page memory, an image is written in synchronization with a scanner, so that the paper is delayed. I was unable to instantly rescan from the leading edge of the document. Therefore, the paper arrives at this position at the registration position by the time the paper is originally sent out due to the delay in the paper feed timing due to paper quality, humidity, static electricity, etc., or the decrease in the transport speed due to wear of the feed rollers. If not, the paper jams in the paper conveyance path, that is, paper jam occurs (JAM: jam). This JA
There was a problem that the apparatus was stopped by M, and recording (copying in the case of a copying machine) had to be performed again. An object of the present invention is to provide a digital image forming apparatus capable of rewriting an image at an arbitrary timing even when the paper feeding timing is delayed.

[0004]

In order to achieve the above object, the invention of claim 1 has a page memory, and after starting writing an image on the photosensitive drum, the sheet is moved from the registration position at the timing of tip alignment. In a digital image forming apparatus having a registration control means for sending out, a means for storing image data in a page memory at the same time as scanning a document, and a method for registering a sheet when the arrival at the registration position of the sheet is later than a predetermined time. With a means to stop at the ration position,
The registration control means is configured to rewrite the image in the page memory from the beginning again when the paper arrives at the timing of the predetermined registration position after the start of image writing and the paper is not in time. .

[0005]

With the above construction, when a paper delay occurs, the paper is stopped at the registration position, and
Disables the image being written. After that, when the sheet reaches the registration position, the previously invalidated image is read from the page memory and rewritten. At this time, the image writing timing when the paper is delayed can be arbitrarily adjusted from the time when the paper reaches the registration position with a delay. Therefore, when the paper delay is within the predetermined time, the JAM is not detected and the device is stopped by JAM. It can be lost.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is applied to a digital copying machine. FIG. 3 shows a block diagram related to registration control. Here, as the means for holding the paper at the registration position, the one using the registration gate will be described, but the same applies to the registration roll. An original image is read by the image information reading device (original scanner) 10, and the image information is subjected to image processing in the image editing / processing device 11 and stored in the page memory 13 via the memory controller 12. On the other hand, with respect to the paper, in synchronization with the start of the document scanning, the feed roller is driven by the paper conveying device 14 (the drive source of the dotted frame portion in FIG. 1) including a feed motor and a feed clutch to feed the paper from the paper tray to the register. At the same time as sending, the registration control device 16 receives a registration gate open signal and drives the sending roller to send the paper to the photoconductor.

The image writing device 15 writes an image on the photoconductor based on the image information read from the page memory 13 in response to the paper detection signal from the paper feed sensor SNR1 output from the registration control device 16. Further, during the image writing, if the sheet detection signal of the registration sensor SNR2 is not input from the registration control device 16 even if a predetermined time has elapsed, the image being written is invalidated.
After that, when the sheet detection signal of the registration sensor SNR2 is input, the invalidated image is read from the page memory 13 and the writing of the image is started again.

Since the registration control device 16 matches the timing of starting the opening of the registration gate (driving in the case of the registration roller) (paper feeding timing) and the image writing timing of the image writing device 15,
The registration gate is opened based on the sheet detection signal of the registration sensor SNR2. That is, the opening of the registration gate is notified to the sheet conveying device 14, the sending roller is driven, and the sheet is sent toward the photoconductor. When the registration sensor SNR2 does not detect a sheet within a predetermined time from the start of writing an image, that is, when the sheet is delayed, the registration sensor SNR2 detects the sheet and notifies the image writing device of the sheet. Control the opening of the. Next, the operation of this embodiment will be described. FIG. 4 shows a timing chart of registration control of this embodiment. FIG. 5 shows a flowchart of registration control of this embodiment. Here, registration control will be described when the sheet has not reached the registration gate within a predetermined time after the start of image writing, that is, when the sheet arrives with a delay.

Simultaneously with the start of document scanning, image data is fetched and held in the page memory (S1). Image writing is started on the paper fed from the paper tray (S2). Timing at which the registration gate should be turned on immediately after the fed paper steps on the registration sensor SNR2 (T
It is determined whether or not 3) has been reached (S3), and when T3 has not been reached, the sheet is stopped when the sheet arrives at the registration gate (S4). On the other hand, when T3 is reached, it is determined whether or not the paper arrives at the cash register (S5). When the paper arrives at the cash register, the cash register is opened and the paper is sent to the photoconductor (S6). When the paper has not arrived at the register, the writing of the image is stopped, that is, the image being written is invalidated (S7). Then, it is determined whether the registration sensor SNR2 detects a sheet (SNR2 → ON) (S8), and when it is detected that the sheet arrives at the registration gate, the writing of the previously invalidated image is started (S2). At this time, the paper reaching the cash register is stopped at the cash register. After T3 from the writing again, the stopped paper is sent out from the register, and the leading edge of the written image is adjusted. Here, the rewriting of the image is performed only on the paper having the delay.

[0010]

As described above, according to the present invention, when the paper feed timing is delayed with respect to the image writing timing, after the paper reaches the registration position, rewriting can be performed at any timing. Therefore, JAM does not occur even when the paper is delayed, and the recording operation is continuously performed, so that productivity is not reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of registration control in an image forming apparatus.

FIG. 2 is a timing chart of image writing and paper feeding of a conventional image forming apparatus.

FIG. 3 is a block diagram related to registration control of the present invention.

FIG. 4 is a timing chart of image writing and paper feeding according to the present invention.

FIG. 5 is a flowchart of registration control of the present invention.

[Explanation of symbols]

1 ... Photosensitive member (drum), 2 ... Image writing position, 3
… Paper tray, 4… Paper, 5… Registration gate

Claims (1)

[Claims] 1. A digital image forming apparatus having a page memory and having registration control means for feeding a sheet from a registration position at a timing for aligning the leading edge after writing an image on a photosensitive drum, and an image is simultaneously scanned with an original. The registration control means includes means for storing data in a page memory and means for stopping the paper at the registration position when the paper reaches the registration position later than a predetermined time. A digital image forming apparatus characterized in that, after the writing is started, when the paper is not in time for the paper delivery timing from a predetermined registration position, the image in the page memory is rewritten from the beginning in accordance with the arrival of the paper.