JPH02199472A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of jitters which are caused by the vibration of counting action by setting the timing of counting for the total paper counter for deciding the service life of the device for other than the time when any image is optically written on a photosensitive body. CONSTITUTION:When an optically writing permission signal from a CPU 5 controlling the engine of the image forming device is sent to an optical writer 6, optical writing is carried out during a period in response to image size. After a prescribed length of time from the completion, a signal counting up the paper volume counter 4 is generated to count paper. A period from when a next image writing permission signal is generated after the current image writing permission signal plays its role is set constant regardless of paper size. Since the short count timing comes under this period, the counter can start counting any time other than the image writing timing. Consequently, jitters caused by vibration can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image forming apparatus that performs optical writing on a photoreceptor to transfer and record a toner image formed on the photoreceptor onto transfer paper.

Prior Art In image forming apparatuses such as optical printers, optical facsimiles, and digital copiers, optical writing is performed on a photoconductor using a beam of light such as a laser beam that carries an image information signal, and information is formed on the photoconductor by an electrostatic photographic process. The toner image is transferred from the paper feed section to the transfer paper fed to the transfer section along the photoreceptor under the action of a transfer charger, and after the transfer, the transfer paper is separated from the photoreceptor and the toner image is transferred to the transfer paper. The image is fixed and recorded.

The photoreceptor and the main body of the machine deteriorate over time due to repeated image formation and reach the end of their service life. In practice, it is difficult to judge the lifespan of a photoreceptor or machine by looking at the formed image, so a counter is used to count the cumulative number of sheets of transfer paper that have passed through the machine, and this count is set to a preset value. Generally, a method is adopted in which it is determined that the life has come to an end when the life is reached and a display is made, or the count display on a counter is periodically checked to know when the life has come.

Conventionally, the number of sheets of transfer paper that has passed has been determined by the number of rotations of a photoconductor, regardless of the size of the transfer paper, or by installing a paper discharge sensor in the paper discharge section of the recording paper and counting up a counter based on the detection signal from the sensor. and counting.

FIG. 1 is a diagram illustrating the configuration of an example of a laser printer equipped with a transfer paper sheet counter, excluding the housing.
An optical writing unit 3 equipped with a polygon mirror 2 as an optical deflector for main scanning is provided at the top of the device 1.
A counter 4 is provided on the side of the optical writing unit 3 to count the number of sheets passed.

The counter is normally activated by a solenoid in a pulsed manner each time a count signal arrives, which causes vibrations.If the counter is installed near the optical writing unit, the vibrations of the counter will be transmitted to the optical writing unit, causing polygon mirrors, etc. The optical element vibrates.

FIG. 4 is a timing chart showing an example of the relationship between the timing of optical writing on a conventional photoconductor and the timing of counting by a paper passing counter. For optical writing, the image size is A3. A4.
Even if it changes to A6, the image writing permission signal (F
SYNC) is output and the open writing is performed. F.S.
The YNC signal is a signal with a length equal to the time required to write from the leading edge to the trailing edge of the paper of the image forming size in the conveyance direction, and it goes without saying that the smaller the size, the shorter the length, and the longer the larger size. Nor. On the other hand, the counting operation of the counter is performed in a pulsed manner after a certain time T2 from the photoreceptor position detection signal (home position signal), regardless of the image formation size. Therefore, due to the relationship between the length of T2 and the time required for writing, counting is performed during optical writing when writing a large size image.

When counting is performed during optical writing, the vibration of the counter is transmitted to optical elements such as mirrors of the optical writing unit, causing jitter on the image.

Problems to be Solved by the Invention In view of the above-mentioned problems of conventional image forming apparatuses equipped with a counter, the present invention provides an image forming apparatus that prevents jitter from occurring in images due to vibration caused by counting the number of sheets passed by the counter. The challenge is to provide the following.

Means for Solving the Problems In order to solve the above problems, the present invention is characterized in that the timing for counting the number of sheets passed by the counter is set to a time other than when optical writing is performed on the photoreceptor.

Since the counting timing of the action counter is set to a time other than when optical writing is performed on the photoconductor, even if the vibration caused by the counting operation is transmitted to the optical writing unit and causes the mirror etc. to vibrate, no optical writing is being performed at that point, so the image will not be affected. No jitter occurs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a control block diagram of the optical writing and counting timing of the paper passing counter in the apparatus according to the embodiment of the present invention.

When an optical writing permission signal (FSYNC signal) is issued to the optical writing device 6 from the CPU that controls the engine of the image forming apparatus (a unit including a photoconductor and image forming process equipment), a time period corresponding to the image size is emitted. When optical writing is performed and the FSYNC signal ends, the CPU 5 outputs a signal to count up the number of sheets passed counter 4 after a certain period of time, and the solenoid is energized in a pulsed manner to count up the counter.

Figures 3(a), (b), and (c) are A3. A4゜A6
Image writing permission signal (F
SYNC) and a timing chart showing the relationship between count timing of a counter.

The length of the image write permission signal (FSYNC) varies depending on the paper size, but when continuously forming images on multiple sheets, the time from the end of one image write permission signal to the start point of the next image write permission signal is A constant time T regardless of the paper size. It is said that The count timing of the counter is a constant time T1 after the end of the image write permission signal, regardless of the paper size. This T is shorter than the above-mentioned To. Therefore, regardless of the size, the count timing always occurs between the end of the image write permission signal and the start of the next signal.

Effects As described above, according to the present invention, since the counter counts while avoiding the image writing timing, it is possible to prevent jitter due to counter vibration.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an example of an image forming apparatus to which the present invention is applied, excluding the housing; FIG. Figure 3(a). (b) and (c) are timing charts showing the relationship between the image write permission signal and count timing for each paper size, and FIG. 4 is a timing chart showing an example of the relationship between the image write permission signal and count timing of a conventional device. It is. 1... Image forming device 3... Optical writing unit counter

Claims (1)

[Scope of Claims] An image forming apparatus that performs optical writing on a photoreceptor and records a toner image formed on the photoreceptor by an electrostatic photographic process onto transfer paper, the number of sheets of transfer paper being passed is In a device that has a counter that counts the number of sheets, and the life of the photoreceptor and the machine body is determined by the number of sheets passed counted by the counter, the timing of counting the number of sheets passed by the counter is determined by optical writing on the photoreceptor. An image forming apparatus characterized by a function other than time.