JPS6273281A - Registration adjusting device - Google Patents

Abstract

PURPOSE:To eliminate a deviation in registration by providing a timing adjusting means which adjusts the timing at which a copying form reaches a transfer position according to a reduction/enlargement ratio and aligning the head of an electrostatic latent image with the front end of the copying form by this timing adjusting means. CONSTITUTION:When operation for copying is started, one of feed rollers 34 and 35 of paper feed trays 32 and 33 is driven selectively and desired copying forms 18 are fed, sheet by sheet. The front end of the sent-out copying form 18 abuts on a gate 36 provided in the middle of a conveyance path 21 to form a loop. The copying form 18 whose conveyance is stopped begins to be conveyed again when the gate 36 is opened and reaches the transfer position 23, so that a toner image is transferred. The copying form 18 passes between a couple of fixing rolls 37 and 38 and is fixed thermally and discharged onto a discharge tray 37. Registration is adjusted by controlling the time from when a registration switch 31 detects a lead edge to when the gate 36 is opened.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is a copying machine in which the formation position of an electrostatic latent image on a photoreceptor differs depending on the magnification, and a method for correcting registration errors caused by this. The present invention relates to a registration adjustment device.

``Prior Art'' Various types of copying machines have appeared that are capable of making copies at various reduction ratios. FIG. 7 shows a typical reading system of such a copying machine. A document 2 is placed on a platen glass 1 of this copying machine. A light source 3 for illuminating the original 2 is arranged below the platen glass 1. The light reflected from the document 2 illuminated by the light source 3 passes through the first to third mirrors 4 to 6, the lens 7, and the fourth mirror 8, and then reaches the photoreceptor drum 9-1-.
The exposure point 11 is exposed to slit light.

In this copying machine, when the first carriage 12 to which the light source 3 and the first mirror 4 are attached is moved (scanned) in the direction of the arrow 13 at a predetermined speed 2, the second and third mirrors 5,6 The second carriage 14, to which is attached, moves in the same direction as this at half the speed. As a result, lens 7
The original 2 is scanned while the optical distance to the scanning position of the original 2 is kept constant.

Further, in this copying machine, a third carriage 15 to which a lens 7 is attached is also arranged so as to be movable in the direction of the arrow 13 or in the opposite direction. When the positions of the second and third carriages 14 and 15 are moved with the mirror 8 fixed, the ratio of the optical distance between the lens 7 and the scanning position of the original 2 and the optical distance between the lens 7 and the exposure point 11 changes. changes, thereby making it possible to change the horizontal magnification of the copying magnification. The vertical magnification can be set by the ratio between the moving speed of the first carriage 12 and the peripheral speed of the photosensitive drum A9.

In such a conventional copying machine, the second carriage 14 changes its scanning start point according to the reduction ratio. Therefore, a space for this is required near the second carriage 14. Reducing the size of a copying machine by securing such space is often accompanied by considerable difficulty.

Therefore, a copying machine has been proposed in which the scanning start point of the second carriage can be fixed. FIG. 8 shows the main parts of this copying machine. In this copying machine, various reduction ratios are realized by moving the lens 7 and the fourth mirror 8. Mirrors 8Δ and 8B located at two locations in the figure represent the respective set positions of the fourth mirror 8 at the same magnification and at a certain reduction ratio.

"Problem to be Solved by the Invention" In the proposed copying machine, there is no need to move the third and fourth mirrors 5.6 when changing the magnification ratio, so that the space around these mirrors is saved. I can do it. However, since the fourth mirror 8 is moved on the optical axis of the lens 7 instead, the position at which the reflected light is incident on the photosensitive drum 9 differs depending on the magnification. In the figure, exposed area 11A,
IIB corresponds to mirrors 8A and 8B, respectively. If the exposed areas are different, a so-called registration error occurs.

That is, the copy sheets 1 stacked on the supply tray 17 now
8 is fed out by the feed roll 19 at a predetermined timing. The copy paper 18 advances along a conveyance path (not indicated by a broken line 21) and reaches a transfer position 2 where a transfer corotron 22 is present.
3, the toner image will be transferred. If the leading edge of the electrostatic latent image reaches the transfer position 23 at time TI, which is a time t1 after the leading edge of the electrostatic latent image is formed at the exposure location 11A at the same magnification, then the leading edge of the copy paper 18 will arrive at the transfer position 23 at this time T1. When the transfer position 23 is reached, the leading edge of the copy paper 18 and the leading edge of the toner image 25 coincide as shown in FIG. 3A, indicating that registration has been accurately performed. However,
If the formation of an electrostatic latent image is started from another exposure point 11B under the condition that the same timing adjustment is performed, the leading edge of the toner image will reach the transfer position 23 in a time shorter than time t. I end up. Therefore, when the leading edge of the copy paper 18 reaches the transfer position 23 at time T1, the leading edge of the toner image has already passed there, and as shown in FIG. will be transcribed into. Even if the registration is set at the same magnification as described above, if the reduction ratio is changed, the leading edge of the copy paper 18 and the toner image 25 will no longer match, resulting in a misregistration.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a registration adjustment device that does not cause such a registration error even in a copying machine in which the magnification is set by moving the fourth mirror 8.

"Means for Solving the Problem" In the present invention, the registration adjustment device is provided with a timing adjustment means for adjusting the arrival timing of the copy paper at the transfer position in accordance with the reduction ratio, and the timing adjustment means is used to stabilize the copy paper. Align the leading edge of the electrostatic latent image with the leading edge of the copy paper. Here, the timing adjustment means can perform various timing controls depending on the copying machine. For example, in a copying machine that controls the timing at which the copy paper reaches the transfer position by temporarily stopping the copy paper and then adjusting the time until it starts transporting, What is necessary is to prepare a timing adjustment means to adjust the timing. In addition, in a type of copying machine that controls the timing at which the copy paper reaches the transfer position by controlling the conveyance speed without stopping the conveyance of the copy paper, timing adjustment that adjusts the conveyance speed according to the reduction ratio is necessary. All you have to do is prepare the means.

"Example" The present invention will be described in detail below with reference to Examples.

FIG. 1 shows the main parts of a copying machine using the registration adjustment device of this embodiment.

Components that are the same as those in FIGS. 7 and 8 are designated by the same reference numerals, and their descriptions will be omitted as appropriate.

The first carriage of this copying machine is provided with a microswitch (hereinafter referred to as a register switch) 31 for detecting the lead edge (starting point of reading) of a document. The registration switch 31 comes into contact with a projection (not shown) to detect this timing when the first carriage 12 moves to a certain extent from the scanning start position and starts scanning the lead edge.

By the way, this copying machine has two paper feed trays 32 and 33.
is provided. Once the copying process begins,
One of the feed rolls 34.35 of each of these paper feed trays 32.33 is selectively driven, thereby feeding desired copy sheets 18 one by one. The leading edge of the fed-out copy paper 18 hits a gate 36 provided in the middle of the conveyance path 21, forming a loop as shown. The copy paper 18 whose conveyance has been stopped in this state starts being conveyed again when the gate 36 opens, and reaches the transfer position 23, where the toner image is transferred.

The copy paper 18 is then passed through a pair of fixing rolls 37 and 38.
The paper passes through the space, is thermally fixed, and is discharged onto the discharge tray 39. Registration adjustment is performed after the registration switch 31 detects the lead edge and then the gate 3
This is done by controlling the time until 6 opens.

FIG. 2 shows the circuit configuration of the registration adjustment device of this embodiment. The CPU (central processing unit) 40 of this device is also used for other controls such as the copying operation of the copying machine, and receives a machine clock 41 to perform various timing controls. It is connected to each part of the machine and processes data. Of these, the ROM 43 is a read-only memory in which the aforementioned gate opening/closing control program and the like are written. The RAM 44 is a working random access memory used for data calculation work and the like.

The non-volatile memo IJ (NVM) 45 is a memory backed up by a battery, and in this embodiment stores the time until the gate is opened in association with the reduction ratio. The input interface 46 includes a numeric keypad 47, a fixed magnification button 48, and an increase button 49 for arbitrary magnification.
, a reduction box 50 for arbitrary magnification, a start button 51,
This is an interface for sending data input from various switches such as the register switch 43 described above to the pass line 42. Further, the output interface 53 has 7
Solenoid 5 for controlling opening/closing of the segment display 52, display line group 55, or gate 36
This is an interface that supplies display data and control data to devices such as 6.

FIG. 3 shows a portion of the console panel of the copying machine that is related to the registration adjustment device of the present invention. The 7-segment display 52 located at the left end in the figure is a 3-digit display normally used to display the number of copies, but in the device of this embodiment, it displays manual data written to the non-volatile memory 45. It is supposed to be done. 7 on console panel 57
A fixed magnification button 48 is arranged below the segment display 52. When the fixed magnification button 48 is pressed, the six display lamps 55 arranged on the right side thereof will be displayed. ~55
6 are selectively turned on one by one, and six types of fixed magnifications are selected one by one. Further below the fixed magnification button 48, an arbitrary magnification increase button 49 and an arbitrary magnification decrease button 50 are provided. These buttons 49 and 50 are used to arbitrarily set the reduction magnification in 1% increments; pressing the arbitrary magnification increase button 49 increases the magnification, and pressing the arbitrary magnification decrease button 50 decreases the magnification. Pressing one of these buttons 49, 50 will turn on the six fixed magnification indicator lights 55. until a new fixed magnification button is pressed. ~556 are all turned off.

Display lamp group 55. ~ On the right side of 556, there is a numeric keypad 47
and a start button 49 are arranged.

The numeric keypad 47 is used for manually inputting the number of copies, but in the apparatus of this embodiment, it is also used for inputting data to the nonvolatile memory 45 manually. The start button 49 is pressed not only when instructing the copying machine to start copying, but also when inputting numerical data using the numeric keypad 47 and ending data manually.

Regarding the registration adjustment device having such a configuration, the registration adjustment operation will first be explained with reference to FIG. 4. When the operator of the copying machine completes copy preparation by operating the fixed magnification button 48 (FIG. 3) and presses the start button 51 (steps ■, Y), the CPLJ40
reads out the reduction ratio M written in the RAM 44, and reads out the corresponding correction value from the nonvolatile memory 45 (steps ①, ①). The following Table 1 shows the relationship between the reduction ratio M and the correction value.

(Margins below) Table 1 For example, when the copying machine operator sets the reduction ratio M to 155%, the numerical value 6 is read out as the correction value. The CPU 40 performs the following calculation based on the correction value (step 2).

0-D Here, the numerical value 70 represents the number of machine clocks 41 generated from the time of detection by the registration sensor 31 until the gate 36 is opened when the correction value is zero. That is, in the apparatus of this embodiment, when the gate 36 is opened when 70 machine clocks 41 have been generated after the registration sensor 31 detects the scanning start position, the electrostatic latent image formed at the exposure point 11A at the same magnification is removed. The leading edge of the copy paper 18 coincides with the leading edge of the copy paper 18 at the transfer position. Other exposed locations are located close to the transfer position 23, such as the illustrated exposure location 11B, so the closer they are to the transfer position 23, the larger the correction value is, and the earlier the gate 36 is opened, the more the resist The aim is to adjust the ration. The above-described magnification M
When is 155%, the number of corrected machine clocks 41 is equal to 4. This is about 1.5mm copy paper 18
This will allow the registration to match.

The calculation results obtained as described above are stored in the RAM 44. When the registration sensor 31 detects the scanning start position (step ■; Y), the machine clock 41 starts counting (step ■), and when the calculation result matches (step ■; Y), the solenoid 56 is energized and the gate 3
6 will be opened (step ■). In this way, it is possible to match the registrations with sufficient precision for all reduction ratios.

Incidentally, depending on the copying machine, it may be better to partially change the correction value in relation to the reduction ratio M. In the registration adjustment device of this embodiment, since the correction value is written in the nonvolatile memory 45 in association with the reduction ratio M, such a change is possible.

FIG. 5 shows the work flow for this purpose.

Writing data to the nonvolatile memory or changing the written data is carried out by a service person who maintains or repairs the copying machine by setting the copying machine to a self-diagnosis mode (step 2). The self-diagnosis mode is a mode for inspecting each part of the copying machine, but in this embodiment, it is also used as a mode for inputting data to the registration adjustment device. Self-diagnosis mode can be set by pressing a special switch inside the copier. Depending on the copier, numeric keypad 4
This mode can be set by operating 7 etc. in a special combination.

When the copying machine is set to the self-diagnosis mode, the service person inputs a code specially prepared for the registration adjustment device (registration adjustment code) from the numeric keypad 47, and presses the start button 51 (step 2). Thereafter, the reduction ratio M for changing data or inputting new data is set using the optional increase button 49 for magnification (step 0). The setting of this reduction ratio M is confirmed by pressing the start button 51 (step 0). The service person then inputs a correction value corresponding to this reduction ratio M using the numeric keypad 47 (step [phase]). Correction value start button 5
1 is pressed, the pair of values M and D are definitely written in the corresponding memory area of the non-volatile memory 45 (step 2).

Thereafter, by inputting the registration adjustment code again from the numeric keypad 47, other combinations of the reduction ratio M and the correction value are written into the nonvolatile memory 45 in the same procedure (steps 0 to 0).

After writing the necessary data as described above, the service engineer inputs a termination code that is different from other self-diagnosis codes (Step 0; N; Step @;
N). This cancels the self-diagnosis mode. On the other hand, if the other self-diagnosis code described above is input, then the self-diagnosis will be executed (step ＠)).

"Modification" In the embodiment described above, the conveyance of the copy paper is temporarily stopped and the time at which the copy paper reaches the transfer position is controlled by the timing at which the gate is opened, but the speed is controlled without stopping the conveyance. The arrival time can also be controlled by

FIG. 6 is a diagram for explaining the principle of registration adjustment with respect to an example of such a registration adjustment device. From the paper feed tray 33 to the feed roll 3
The leading edge of the copy paper 18 sent out by the copy paper 5 is detected by an optical sensor 61. Copy paper 1 at this time
The detection time of 8 varies depending on the slip of the feed 0-roller 35, etc., and therefore is not constant. Previously, the patent application
As seen in the specification of Japanese Patent Application No. 3634, the conveying speed is continuously changed to correct this error, so that the transfer position 23 is reached at a predetermined time. Therefore, if the conveyance speed is controlled taking into account the shift in the exposure position due to the reduction ratio M, and the arrival time of the copy paper is adjusted, the transfer position 23
The leading edge of the electrostatic latent image and the leading edge of the copy paper 18 can be made to coincide with each other.

"Effects of the Invention" As explained above, according to the present invention, the registration error caused by the positional shift of the electrostatic latent image on the photoreceptor-L is corrected by adjusting the arrival timing of the copy paper at the toner image transfer position. This eliminates the need to fix part of the mirror, increasing the degree of freedom in designing the optical system.

[Brief explanation of drawings]

1 to 5 are for explaining one embodiment of the present invention, of which FIG. 1 is a schematic horizontal diagram showing an outline of a copying machine using a registration adjustment device, and FIG. A circuit block diagram of the registration lane adjustment device, Fig. 3 is a plan view showing a part of the operation panel, Fig. 4 is a flowchart showing the flow of gate control operation, and Fig. 5 is writing of data to nonvolatile memory. 6 is a principle diagram for explaining a modified example of the present invention, FIG. 7 is a schematic configuration diagram showing an example of a copying machine in which a part of the mirror is fixed, and FIG. Schematic configuration diagram of a copying machine with a movable mirror, No. 9
FIGS. (Δ) and (B) are explanatory diagrams showing changes in the transfer position of a toner image as the magnification changes in the proposed copying machine. 9...Photosensitive drum, 18...Copy paper, 23...Transfer position, 31...Register switch, 36...Gate, 40...
cpu. 41...Machine clock, 3...RO
M. 45...Non-volatile memory, 56...Solenoid. Applicant: Fuji Xerox Co., Ltd. Agent

Claims (1)

[Claims] 1. An electrostatic latent image whose tip position differs depending on the magnification of the document is formed on the surface of a photoreceptor moving at a predetermined speed, and this is developed to form an electrostatic latent image on the surface of the photoreceptor. In a copying machine that transfers a toner image at a fixed transfer position to copy paper moving at approximately the same speed, a timing adjustment means is provided for adjusting the arrival timing of the copy paper at the transfer position according to the reduction ratio. 1. A registration adjustment device, characterized in that the timing adjustment means causes the leading edge position to match the leading edge of the copy sheet. 2. In a copying machine that controls the timing at which the copy paper reaches the transfer position by temporarily stopping the copy paper before it reaches the photoconductor, the timing at which the copy paper starts to be conveyed after it has been stopped is set to the reduction ratio. 2. The registration adjustment device according to claim 1, further comprising timing adjustment means for adjusting accordingly. 3. In a copying machine that controls the arrival time by continuously changing the transport speed of copy paper before it reaches the photoreceptor,
2. The registration adjustment device according to claim 1, further comprising timing adjustment means for adjusting the state of change in the conveyance speed according to the reduction ratio.