JPH03225378A - Exposure control system for color recorder - Google Patents

Abstract

PURPOSE:To carry out high-definition color recording by identifying a gripper arriving at a sensitized drum, reading out exposing timing information from an exposing timing information storage part corresponding to the relevant gripper, and carrying out an exposure based on the information. CONSTITUTION:When the arrival of a gripper 204 is detected by a gripper detecting sensor 230I, a control part 31 outputs an enabling signal to a counter part 41b and an LED driver part 43 after the lapse of a prescribed time, and the counting of a reference clock and the action of the driver part 43 are started. Simultaneously, a switch 46 is changed over by the classifications of the arrival grippers 204. At this time, a gripper 1 arrives and a ROM part 42a is selected. An exposing timing signal is generated by a resistor part 41c based on the exposing timing information stored in the relevant ROM part 42a, and an image is exposed. Thus, an error in the carrying speed of the sensi tized drum 210 and gripper 204 is removed and the image is recorded at a prescribed position on a recording medium.

Description

[Detailed description of the invention] (Table of contents) Overview Industrial field of application Prior art (Fig. 11.12) Problem to be solved by the invention (Fig. 10.12) Means for solving the problem (Fig. 1 .2) Effects (Figs. 1 and 2) Example (Figs. 3 to 9) Effects of the invention [Summary] They are installed side by side, each forms a color-separated image, and is exposed to light based on the instructed timing. Regarding a color recording device that has a photosensitive drum and a gripper that grips and conveys recording paper, and obtains a color image by sequentially overlapping recording on the recording paper that is conveyed by the gripper, the photosensitive drum and the gripper that feeds the paper are In order to reduce the printing positional deviation between each color that occurs when printing each color overlappingly on the recording paper due to speed errors in both grippers and errors in the mounting position of the gripper on the conveyor belt, the an exposure timing information storage unit that stores predetermined exposure timing information related to recording on one recording paper, which is created in association with each gripper based on the characteristics;
The configuration includes an exposure signal generation section that identifies a gripper arriving at each photosensitive drum, reads out exposure timing information from an exposure timing information storage section corresponding to the gripper, and generates an exposure timing signal based on the exposure timing information. be.

[Industrial application field]

The present invention is an electrophotographic recording apparatus, in particular, in which a plurality of photosensitive drums are installed side by side, color-separated images are formed on each photosensitive drum, and the images are sequentially overlaid and recorded on a recording paper conveyed by a gripper. The present invention relates to an exposure control method for a color recording device that obtains images.

Although this type of recording apparatus has the advantage of being able to perform high-speed color recording, it is easy for the recording positions of each color to be misaligned, making alignment an important issue.

[Conventional technology]

Conventionally, there has been a color recording apparatus as shown in FIG.

This device shows an example of a color recording device using four photosensitive drums 810, including a recording paper cassette 801,
A feeding roller 802, a registration roller 803, a gripper 804, a belt 805 that conveys the gripper,
It has a driving pulley 806 for a belt 805. The grippers 804 are provided on the conveyor belt 805 at approximately equal intervals. Sensor 830.83 also detects the arrival of Yuba Tsuba.
As shown in FIG. 11, 0I to 830■ consist of a rotatable lever 831, a transmission type optical sensor 833 that detects the movement of the lever 831, and a coiled spring 832 that provides restoring force to the lever 831. When the gripper 804 arrives, the lever 831 is rotated by the gripper 804, and the light from the light emitting side of the optical sensor 833, which is normally blocked, reaches the light receiving side. The sensors 830° 830■ to 830■ output this change as a gripper detection signal as a pulse to a control section (not shown).

The recording process (Steps to ■) is composed of the same members, including a photosensitive drum 810, a charger 811, an exposure system 812 using an LED array, and a developer 813.
, a transfer device 814 , and a cleaner 815 . These are installed in four sets (from 1 to 2) at equal intervals.

Next, the operation will be explained. First, when the sensor 830 detects the arrival of the gripper 804, the controller (not shown)
00 starts to be supplied, the leading end of the recording paper 800 is held by a gripper 804, and the recording paper 800 is sent to a recording section consisting of recording processes E to (3).

In each recording section, color toner images are superimposed on the recording paper in the order of (1) to (2) to perform color recording consisting of a plurality of colors.

After overlapping recording of four colors, the recording paper is sent to a fixing device 820, and the toner image is fixed on the recording paper by heat and pressure applied from a fixing roller 821 and a pressure roller 822, completing a series of color recording processes. .

[Problem to be solved by the invention]

By the way, if there is a shift in the recording position on the recording paper between the colors recorded separately during conventional overlapping recording, the image quality will deteriorate, so it is necessary to match the recording positions of the colors. The recording position at the beginning of the recording paper is, for example,
As disclosed in Japanese Patent Application No. 9-155870, the arrival of the recording paper can be detected by sensors 830 to 830 installed in front of each photosensitive drum, and the exposure start timing can be adjusted by determining the exposure start timing. However, with respect to the recording position within the recording paper, a deviation occurs in the recording position between each color due to speed errors of both the photosensitive drum and the gripper that feeds the paper. In particular, when a gripper is used, errors tend to occur due to positional deviation due to the gripper depending on how the gripper is attached to the conveyor belt.

As shown in FIG. 10, the components of positional deviation can be roughly divided into low frequency components due to eccentricity of shafts and gears, and high frequency components due to pitch errors of timing belts and gear teeth. Among these, the high frequency component has a small amplitude and has little effect on positional deviation. However, the low frequency component has a large amplitude and has a large influence on positional deviation.

It is possible to prevent the recording position shift by increasing the machining and assembly accuracy of the shaft and gears and reducing the fluctuations in the feed rate, but this has the drawback of causing a significant increase in cost.

Therefore, in the present invention, we focused on the fact that the positional deviation is reproducible due to the unique characteristics of each gripper and each photosensitive drum. Based on this, the exposure timing that minimizes the deviation is determined for each recorded color, and the exposure timing is stored in a separate storage unit, and at the time of exposure, the image data is exposed based on the exposure timing information read from this storage unit. By doing so, the printing position of each color is set to approximately a predetermined position, and the printing position deviation between the colors is reduced.

[Means to solve the problem]

In order to solve the above-mentioned technical problems, a first invention has been developed, as shown in FIG. , a gripper 1 that grips and conveys a recording paper, and obtains a color image by sequentially overlapping recording on the recording paper conveyed by the gripper 1. The exposure timing information storage unit 4 stores predetermined exposure timing information related to the recording of one recording paper, which is created in association with each other, and the gripper 1 arriving at each photosensitive drum 2 is identified, and the gripper 1 is An exposure signal generating section 3 is provided which reads the exposure timing information p from the corresponding exposure timing information storage section 4 and generates an exposure timing signal based on the exposure timing information.

On the other hand, the second invention, as shown in FIG. 2, is a photosensitive drum 2 which is installed side by side and forms a color-separated image on each drum and is exposed to light based on an instructed timing, and a recording paper is sandwiched and conveyed. In a color recording device that has a gripper 1 that sequentially performs overlapping recording on a recording paper conveyed by the gripper 1 to obtain a color image, a color recording device is provided that is associated with each photosensitive drum 2 based on the unique characteristics of each photosensitive drum 2. Reads exposure timing information from the exposure timing information storage unit II 6 that stores predetermined exposure timing information related to recording on one recording paper created and the exposure timing information storage unit II 6 corresponding to each photosensitive drum 2, An exposure signal generating section II 5 is provided which generates an exposure timing signal based on the exposure timing information.

[Effect]

The first invention of the exposure control method for a color recording apparatus according to the present invention operates as follows. As shown in FIG. 1, the exposure signal generating section 3 identifies the gripper 1 that arrives at each photosensitive drum 2, and stores the unique characteristics of each gripper in advance from the exposure timing information storage section 4 corresponding to the gripper 1. Based on this, the exposure timing information recorded for each gripper is read out, an exposure timing signal is generated based on the exposure timing information, and image data is exposed using the exposure timing signal.

On the other hand, the second invention operates as follows. As shown in FIG. 2, when the exposure timing of each photosensitive drum is controlled in the exposure signal generating section II 5, the unique characteristics of each photosensitive drum are stored in advance from the exposure timing information storage section II 6 corresponding to each photosensitive drum. Based on this, the exposure timing information recorded on each photosensitive drum is read out, an exposure timing signal is generated based on the exposure timing information, and image data is exposed using the exposure timing signal.

〔Example〕

Next, embodiments according to the first invention and the second invention will be described in detail based on FIGS. 3 to 9. Figure 3 shows three grippers 2
04 is an explanatory diagram of a color recording apparatus using four types of photosensitive drums 210.

The blade collar identification sensor 250 for identifying the clipper 204 in FIG. 3 includes a reflective optical sensor for detecting a hole provided in the clipper collar, as shown in FIG. 9. The gripper identification sensor 250 is installed at a position where each reflective optical sensor is below the hole position of the gripper when the gripper detection sensor 230 detects the arrival of the gripper 204. Also, a recording paper cassette 201, a feeding roller 202, a registration roller 203, and a gripper 20
4, a belt 205 for conveying the gripper, and a driving pulley 206 for the belt.
5 at approximately equal intervals.

FIG. 4 is a block diagram of the entire exposure control system, which includes a control unit 31 that performs processing based on the detection outputs of the gripper detection sensors 230, 230 to 230 and the gripper identification output of the gripper identification sensor 250, and each photosensitive drum 210. (I~
■) Each LED exposure control system 37I to 37 that controls the exposure of
It consists of an IV and an oscillator 36.

FIG. 5 is a block diagram of one exposure control system, in which the oscillator 36
, a counter section 41b that counts the clock output from the oscillator 36, and a ROM (read only memory) section 42a that stores the exposure timing for each gripper.
42C (corresponding to the exposure timing information storage section 4) and ROM sections 42a to 42c according to the clock from the oscillator 36.
(Here, the control section 31, the counter section 41b, the register section 41c, etc. correspond to the exposure signal generation section 3 and the exposure signal generation section II5).
, has an image memory section 44 that stores image data, and an LED driver section 43 that reads image data for each line from the image memory section 44 and drives an LED (light emitting diode) 45 that is an exposure light source. Also, each RO
The output terminals of the M units 42a to 42c are connected to the register unit 41c so that the corresponding ROM unit is selected by a switch 46 that is switched according to an instruction from the control unit 31.

Next, each ROM section 42a to 42C (and each ROM section of the other three exposure control systems (not shown) (exposure timing information storage section 4 and exposure timing information storage section II)
A method for creating the exposure timing information stored in (corresponding to No. 6) will be explained.

First, there are a total of 12 types of photosensitive drums and 3 types of grippers.
0.5m over the entire length of the recording paper per street combination
A pattern of horizontal lines is recorded at a constant pitch of about m. The density of this is measured using a microdensitometer as shown in FIG. 6, and the pitch of each line pattern is measured. The measured line pitches are accumulated to obtain the waveform shown in FIG. A low-pass filter is applied to this waveform, leaving only the low frequency components. From the data thus obtained, the exposure timing at which the recording line is closest to the predetermined position is determined. Here, the clock frequency of the oscillator 36 was twice that of the recording line clock. The obtained exposure timing information is recorded in the ROM section, for example, in the case of FIG. 7, 1 at address 0, 1 at address 1, 1 at address 2, 1 at address 3, and so on. This operation is performed for a total of 12 combinations of each color (photosensitive drum) and each blade collar, and the respective exposure timing information is written in the ROM section of each LED exposure control system.

Next, the operation of this embodiment will be explained.

When the gripper detection sensor 230 detects the arrival of the gripper 204, the control unit 31 issues a paper feed command, and the feeding roller 202 takes out the recording paper 200 from the paper cassette 201. Furthermore, the gripper identification sensor 250 identifies which of the three types of grippers 204 the gripper 204 that has arrived is, and outputs the identification signal to the control unit 31 . Further, the taken-out recording paper 200 is temporarily stopped by the registration rollers 203 and the timing with the gripper 204 is determined, and then sent out from the registration rollers 203 at a speed slightly higher than the feeding speed of the gripper 204.
It will be done. When the leading edge of the recording paper enters the gripper 204,
The gripper 204 closes and grips the recording paper 200. After that, the registration roller 203 returns to constant speed rotation.

Next, a time chart in the recording process (I) will be explained with reference to FIG. When the gripper detection sensor 230 detects the arrival of the gripper 204, a predetermined time (Ty
) After that, the control unit 31 outputs an enable signal to the LED exposure control system (1), that is, the counter unit 41b and the LED driver unit 43, and controls the reference clock count and the LE
The operation of the D driver section 43 is started.

At the same time, the switch 46 is switched depending on the type of gripper 204 that has arrived. Here, the gripper 1 has arrived, the ROM section 42a is selected, and the register section 41e is selected based on the exposure timing information stored in the ROM section 42a.
An exposure timing signal is generated and exposure of the image in the recording process is started. In this exposure, RO
Since exposure is performed according to the exposure timing information read from the M section 42a, errors in the conveyance speeds of the photosensitive drum 210 and the gripper 204 are eliminated, and the image is recorded at a predetermined position on the recording paper.

Recording is performed in the same manner in other recording processes II to (2).

After the overlapping recording of the last recording process (IV) is completed, the image is fixed on the recording paper 200 by the fixing device 220, and a series of color recording processes are completed.

In this way, since the recording position in each recording process can be approximately at a predetermined position, positional deviation between colors can be significantly reduced.

Furthermore, in this embodiment, a case has been described in which a ROM unit is used that stores exposure timing information for each type of gripper and photosensitive drum combination, but if the difference in exposure timing for each photosensitive drum is small compared to the gripper, RO that stores exposure timing information that corresponds only to each gripper type
M portion may also be used. This case corresponds to the embodiment of the first invention, and it is sufficient to prepare the same types of ROM sections as the types of grippers. As for the error for each photosensitive drum, for example, a method of taking the average of all the photosensitive drums can be considered.

Similarly, if the difference in exposure timing for each gripper is small compared to the photosensitive drum, a ROM section may be used that stores exposure timing information corresponding only to the type of each photosensitive drum. This case corresponds to the embodiment of the second invention, and it is sufficient to prepare the same type of ROM section as that for the photosensitive drum. Furthermore, regarding the error for each gripper, for example, a method of taking an average for all grippers can be considered.

In this embodiment, LED exposure was used as the exposure means, but similar effects can be obtained in a color recording apparatus using a laser exposure system. Furthermore, the exposure start timing for each color was determined by detecting the gripper 204 by the gripper detection sensors 230I to 230I provided in front of the photosensitive drum.
Of course, the present invention can also be applied to a case where step 230■ is omitted and the exposure start timing for each color is determined based on the output of the gripper detection sensor 230. Furthermore, in this embodiment, the identification sensor of the gripper 204 is replaced by the gripper detection sensor 23.
Although only one is used in the vicinity of the photosensitive drum 210, one may be provided in front of each photosensitive drum 210.

(Effects of the Invention) As explained above, in the present invention, the exposure timing that reduces the positional deviation between each color caused by the unique characteristics of the photosensitive drum and each gripper for each color is determined, and the exposure timing information is used for each photosensitive drum. The image data is stored in separate storage units for each drum and each gripper, and at the time of exposure, image data is exposed based on exposure timing information read from the storage unit.

Therefore, even in a transport system whose transport accuracy is not so high, high-quality color recording with significantly reduced positional deviation between colors can be performed, resulting in excellent effects.

[Brief explanation of drawings]

Fig. 1 is a principle block diagram of the first invention, Fig. 2 is a principle block diagram II of the second invention, Fig. 3 is an explanatory diagram of the drive unit according to the embodiment, and Fig. 4 is a diagram of the entire exposure control system. Block diagram, FIG. 5 is a block diagram of one exposure control system, FIG. 6 is an explanatory diagram (1) for creating exposure timing information, FIG. 7 is an explanatory diagram (2) for creating exposure timing information, and FIG. is a time chart of the recording process (I), FIG. 9 is an explanatory diagram of the gripper, FIG. 10 is an explanatory diagram of recording position deviation, FIG. 11 is an explanatory diagram of the gripper detection sensor, and FIG. 12 is an explanation of the conventional example. It is a diagram. 1.204...Gripper 2.210...Photosensitive drum 3 (31, 41b, 41c, 46)---Exposure signal generation section (control section, counter section. Register section, switch) 4 (42a to 42C) . . . Exposure timing information storage unit (ROM unit) 5 . . Exposure signal generation unit II 6 . I
V) 43...LED driver unit 44...Image memory unit 45...LED 200...Recording paper 201...Recording paper cassette 202...Feeding roller 203...Register roller 205... ...Gripper conveyance belt 206...Belt drive pulley 220...Fixing device 230.230I~230■...Gripper detection sensor 250...Grip blade collar identification sensor Agent Patent attorney Kayo Tsuchibashi=X7: Ding; Ni Maro, ring block diagram 1! 1 Mei Ojin Iku, 119 ahead % ward φ car p1 e August diagram 1i
Figure 3 Figure 2 of the exposure control cloth for the cow body Figure 4 Figure ROM? -ta0110101010100100100100100
10-1 Yuri 1 Mink Joki Garden Sakuhi Attending Meiran Mingzu (2)
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Claims (2)

[Claims] (1) Photosensitive drums (2) installed side by side to form color-separated images on each drum and exposed to light based on instructed timing, and a gripper (1) that grips and conveys the recording paper.
In a color recording device that obtains a color image by sequentially overlapping recording on a recording paper conveyed by a gripper (1), an association is made for each gripper (1) based on the unique characteristics of each gripper (1). The exposure timing information storage unit (4) stores predetermined exposure timing information related to the recording of one recording paper created by Exposure signal generation section (3) that reads exposure timing information from the exposure timing information storage section (4) corresponding to (1) and generates an exposure timing signal based on the exposure timing information.
1. An exposure control method for a color recording apparatus, characterized in that the image data is exposed based on the exposure timing signal. (2) Photosensitive drums (2) installed side by side to form color-separated images on each drum and exposed to light based on instructed timing, and a gripper (1) that grips and conveys the recording paper.
In a color recording device that obtains a color image by sequentially overlapping recording on a recording paper conveyed by a gripper (1), each photosensitive drum (2) has a An exposure timing information storage unit II (6) that stores predetermined exposure timing information related to recording on one recording sheet, which is created in association with each other, and each photosensitive drum (2).
an exposure signal generation section that reads exposure timing information from the exposure timing information storage section II (6) corresponding to the exposure timing information and generates an exposure timing signal based on the exposure timing information;
II(5); and exposing image data based on the exposure timing signal.