JPH032877A - Registration automatic adjustment method - Google Patents

Abstract

PURPOSE:To decrease the fluctuations of the resists between pages by simultaneously and automatically adjusting the longitudinal resist on the front end side of transfer paper and the transverse resist on the transverse end side of the transfer paper. CONSTITUTION:Sensors 14, 15 for detection are disposed in the transporting route of the transfer paper 3 to detect the front end side and transverse end side of the transfer paper 3, respectively. The longitudinal resist on the front end side of the transfer paper 3 and the transverse resist on the transverse end side of the transfer paper are simultaneously and automatically adjusted by adjusting the timing for starting image writing. Namely, A microcomputer (CPU) 19 for the adjustment of the longitudinal and transverse resists and the operation control of a printer, a program necessary for the operation of the CPU 19, and a memory 20 for storing the information, etc., necessary for image formation are provided. The output of a voltage comparator 18 is transmitted by an I/O port 21 through a timing circuit 16 and a bus 22 to the CPU 19. The fluctuations in the longitudinal resist and the transverse resist between the pages are eliminated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for automatically adjusting vertical and horizontal registrations of transfer paper with high precision in digital copiers, laser printers, and the like.

(Prior Art) In conventional recording and transfer devices such as digital copiers and laser printers, when multiple paper feeding and conveyance mechanisms are installed in a system, problems arise due to the parallelism and mechanical variations of each unit.

When the transfer paper is fed from each unit and conveyed to the registration rollers, the horizontal position shifts for each unit, so in order to correct this shift, the transfer paper is positioned in the horizontal direction in front of the registration rollers. Mechanically, corrections were made to match the paper feed cassette's side fence, etc.

In addition, there is also a shift in the vertical position of the transfer paper, and in this case, mechanical correction is performed by abutting the transfer paper against the registration rollers to align the vertical position.

(Problems to be solved by the invention) In general, variations when setting transfer paper in a paper feed cassette or paper feed tray, variations when setting a paper feed cassette or paper feed tray in the machine body, and variations in the transfer paper itself. Due to such factors, it is difficult to avoid variations in the transfer paper in the lateral direction, and the lateral registration varies between pages.

Additionally, variations in the vertical direction occur in conjunction with variations in the horizontal direction, resulting in variations in vertical registration between pages.

In the past, variations in vertical and horizontal registration were mechanically adjusted as described above, but variations had to be checked and adjusted after transfer, which meant that there was no immediate response, and transfer paper and transfer time were wasted. There was a problem with this.

The present invention eliminates such problems by electrically detecting and adjusting variations in vertical and horizontal registrations at the same time, eliminating variations in vertical and horizontal registrations between pages, and improving the edge of the transfer paper. The length of the transfer paper is determined using the time difference between trailing edge detection, and subsequent control 1, for example, jam detection 9 transfer unit.

The purpose is to control duplex units, sorters, etc.

(Structure and operation) In order to achieve the above object, the present invention disposes a detection sensor on the conveyance path of the transfer paper, detects the leading edge side and the lateral edge side of the transfer paper, and adjusts the start timing of writing one image. The apparatus is characterized in that the vertical registration on the leading edge side of the transfer paper and the horizontal registration on the lateral edge side of the transfer paper are automatically adjusted at the same time.

Further, the length of the transfer paper is detected based on the time difference between the detection of the leading edge and the detection of the trailing edge of the transfer paper by the detection sensor.

The present invention uses a COD as a detection sensor to detect the leading edge and lateral edge of the transfer paper, feeds this back to the optical writing control device, controls the writing control timing, and controls the vertical and horizontal registration between pages. This eliminates the variation in

(Example) Fig. 1 shows a main part configuration diagram when the present invention is implemented in a laser printer. To explain the outline of the operation of this printer, transfer paper is fed from a paper feed cassette 1 by a paper feed roller 2. 3 is timed by a registration roller 4 and is conveyed to a drum-shaped photosensitive drum 6 by a conveyance roller 5.

The photoreceptor drum 6 is driven to rotate clockwise, and at this time, the surface is charged by a charger 7 that charges the photoreceptor drum 6, and a laser beam from an optical writing unit 8 modulates a single image signal into laser light. , and an electrostatic latent image is formed on the photoreceptor drum 6.

This electrostatic latent image is visualized by toner when it passes through a developing unit 9 that forms a toner layer.

This visible image is transferred to the transfer paper 3 conveyed to the photosensitive drum 6 by a transfer charger 10 and separated by a separation charger 11, and the transferred and separated visible image on the transfer paper 3 is transferred by a fixing device 12. After being fixed, the paper is ejected or transported through a transport path to a double-sided printing system (reversing unit, double-sided unit), a sorter, or the like.

On the other hand, the cleaning unit 13 removes residual toner from the photoreceptor drum after the visible image has been transferred.

This embodiment is characterized in that a detection sensor consisting of a lamp 14 and a CCD 15 is disposed downstream of the registration roller 4 in the transfer direction of the transfer paper 3 in a part of the transfer paper transport path.

FIG. 2 shows the arrangement of the detection sensors (CCD 15, lamp 14) in the main scanning direction Corresponding to the first element of the CCD 15, the writing start position of the image area R is 5! Z indicates the nth element of CC015. W indicates the writing end position.

In addition, in FIG. 1, when the length between the laser beam irradiation position P on the photosensitive drum 6 and the transfer charger 10 is L, and the distance between the transfer charger 10 and the CCD 15 is L,
Set the relationship L≧Q to ensure tip writing.

FIG. 3 is a diagram showing an embodiment of the vertical registration and horizontal registration adjustment control circuit of the present invention, in which 16 is a timing circuit that generates a clock signal CLK, and 17 is a stop (
Stop)/hold (Hodd) amplifier 18 is a voltage comparator, which determines the presence or absence of transfer paper based on the COD output (Fig. 4) and a preset constant voltage level.
Outputs a stop signal. 19 is a microcomputer (CPU) for adjusting the vertical and horizontal registration and controlling the operation of the printer; 20 is a memory for storing programs necessary for the operation of the CPU 19 and information necessary for image formation; and 21 is an I10 port. The output of the voltage 4 comparator 18 is transmitted to the CPU 19 through the timing circuit 16 and the bus 22.

Next, to explain the operation, before the transfer paper 3 reaches the CCD 15, the CPU 19 issues a start command to the timing circuit 16 via the I10 port 21, and the timing circuit 16 connects the CCD 15 and 5top/Hoa.
A clock (CLK) signal is sent to the d amplifier 17.

In accordance with this clock signal, the level of each element constituting the COD is outputted to the voltage comparator 18 via the Stop/Ho12d amplifier 17. This voltage comparator 18 compares the output of the CCD 15 with the transfer paper 3 present and the output of the CCD 15 with the transfer paper 3 absent.
Judgment is made based on a certain voltage level. That is.

The voltage comparator 18 detects the presence of transfer paper, and then
When it is determined that there is no transfer paper, in other words, when one of the leading edges 3b (FIG. 2) of the transfer paper 3 is detected,
A stop (S top) command is issued to the timing circuit 16, and the timing is also notified to the CPU 19 through the I10 port 21.

FIG. 4 shows an example of the output state of the voltage comparator 18. If the transfer paper 3 arrives while the voltage comparator 18 is checking the output of the 51st element of the CCD 15, the output of the 51st element is The output of the leading edge 3b of the transfer paper 3, here the 29th element, is L.
OW, the output of the CCD 15 is stopped, and the vertical registration is adjusted.

The timing circuit 16 informs the CPU 19 of which element of the CCD 15 has been output, and the CPU uses this information to set the writing start position 2 (
The main scanning direction (X) in FIG. 2 is determined.

Furthermore, since the timing of stopping the output of the CCD 15 is the time when the leading edge 3b of the transfer paper 3 reaches the CCD 15, writing starts after a time T corresponding to L-Ω in FIG. 1, and the transfer paper 3 is fed. The tip portion 3b and the image area R in the sub-scanning direction y) in FIG. 2 are made to coincide with each other.

Next, the deviation correction in the main scanning direction
The first element of D15 (Fig. 2) is at the synchronization detection position Ii! Since it corresponds to S, writing starts from the position corresponding to the CCD element on the lateral edge 3a of the transfer paper 3.Z) When main scanning is performed for 0 paper size, writing for one scan is completed (W). That is, by changing the writing start position (Z) according to the passing position of the transfer paper 3, the deviation in the main scanning direction (horizontal registration) is corrected.

FIG. 5 shows a flowchart of the operation described above.

First, after paper feeding is started, CCD detection is started before the transfer paper 3 reaches the CCD 15 (,).

Next, it is determined from the CCD output (High-+Lov) whether or not the transfer paper has reached the COD (b).

When the transfer paper arrives, data N is set in the counter 1 from the n-th element of the corresponding CCD through which the lateral edge of the transfer paper has passed (C).

The data N of the counter 1 is used to determine the writing start position Z in the main scanning direction X. That is, writing starts at the Nth count from the synchronization detection position S. Furthermore, the transfer paper is C
When reaching OD, reset counter 2.
), and when the time T corresponding to ρ shown in FIG. 1 has elapsed (a), writing is started (f).

In the above operation, from the leading end 3b of the transfer paper 3 to the trailing end 3
The transit time T0 in the sub-scanning direction y to c (Fig. 2) is C
Detected by CD15, its detection output (High->
Low) The length of the transfer paper 3 can be determined by CPU from the time difference. Knowing the length of the transfer paper can be used to detect jams in the registration rollers, or to control the conveyance of the transfer paper to the reversing unit, duplex unit, mailbox, etc.

(Effects of the Invention) As explained above, according to the present invention, the vertical and horizontal registrations of the transfer paper can be easily and accurately adjusted from the COD detection output, so it is possible to reduce the variation in registration between pages. .

Furthermore, since the length of the transfer paper can be measured from the time difference between the detection and appearance of COD, there is an advantage that it can be used for jam detection and other controls.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the main parts when the present invention is implemented in a laser printer, and Figure 2 is the arrangement state and synchronization detection position of the detection sensor that detects the leading edge and side edge of the transfer paper in Figure 1. 3 is a diagram showing an embodiment of the vertical registration and lateral registration adjustment control circuit of the present invention, and FIG. 4 is a diagram showing the relationship between C and C.
A diagram explaining the output of the voltage comparator of FIG. 3 based on the OD detection output, and FIG. 5 is an operation flowchart of FIG. 3. 3... Transfer paper, 3a... Leading edge, 3b... Lateral edge, 3c... Rear end, 4... Registration roller, 6... Photosensitive drum, 14... Lamp , 15...CCD, 16...timing circuit,
17- S top/Hoad amplifier, 18... Voltage comparator, 19... Microcomputer (
CPU), 20...Memory, 21...I10 host, 22...Bus. Diagram

Claims (2)

[Claims] (1) A detection sensor is installed in the transport path of the transfer paper, detects the leading edge and the horizontal edge of the transfer paper, adjusts the start timing of image writing, and adjusts the vertical registration of the leading edge of the transfer paper. An automatic registration adjustment method characterized by automatically adjusting the horizontal registration on the side edge side of transfer paper at the same time. (2) The automatic registration adjustment method according to claim 1, wherein the length of the transfer paper is detected based on the time difference between the detection of the leading edge and the detection of the trailing edge of the transfer paper by a detection sensor.