JPH02250071A - electrophotographic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic apparatus having a copy mode for copying a document image as an analog image and a print mode for optically writing digital information onto a photoreceptor.

[Conventional technology]

In this type of electrophotographic apparatus, in a printing mode in which an LED head consisting of a large number of LBD chips is arranged in the axial direction of a photoconductor, and each chip emits light as appropriate to print.
When running for a long time, the LED head generates heat and its characteristics deteriorate, so conventionally a temperature detector has been installed in the LED head to detect the heat generation, and the output signal can be used to generate a warning signal or forcefully This caused printing to be interrupted.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the printing operation is interrupted when the LED head generates heat to a predetermined temperature, so a reduction in processing speed in the printing mode has been a major problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic apparatus that can prevent an excessive rise in temperature of an LED head due to continuous printing without interrupting printing, and can reduce a decrease in printing processing speed.

[Means to solve the problem]

The above object is to provide an electrophotographic apparatus equipped with an LED head that performs optical writing in a print mode, in addition to an illumination lamp that illuminates a document in a copy mode, in which the LED head is equipped with a temperature detector that detects its temperature; This is achieved by providing the main body with a control means for switching the photoreceptor speed and image forming conditions in the print mode based on the output signal of the temperature sensor.

[Effect]

The temperature detector detects the temperature increase due to the light emission of the LED head,
This data is output to the control means. The control means compares and calculates this data with a reference value, and changes the photoreceptor speed and image forming conditions.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a configuration diagram of an electrophotographic apparatus according to the present invention,
Reference numeral 1 denotes a photoreceptor, around which a charger 2, an LED head 3 for optical writing, an exposure section 4, a developing device 5, a transfer/separator 6, and a cleaning device 7 are arranged in order of the image forming process. ing. Reference numeral 8 denotes a document mounting table on which an original 9 is placed. This image is on the photoreceptor
projected on. 15 is a transfer sheet in a paper feed cassette, 16 is a paper feed roller, 17 is a registration roller, 18 is a fixing roller, and 19 is a paper discharge tray.

The electrophotographic apparatus according to the present invention has a copying mode in which a document 9 placed on a document table 8 is copied, and a printing mode in which printing is performed using an LED head 3 serving as a writing exposure light source.

First, in the copy mode, the scanner 10 exposes and scans the original 9 and forms an exposed image on the photoreceptor drum 1 . The photosensitive drum 1 is driven by a drive motor (not shown) in the rotational direction of the arrow at a speed synchronized with the scanning speed of the scanner 10 .

The photoreceptor 1 is uniformly charged by a charger 2 upstream of the exposure section 4, and then the charge on the non-image area on the photoreceptor 1 is removed by the LED head 3. After that, the electrostatic latent image formed on the photoreceptor l in the exposure section 4 is developed by the developing device 5, and a toner image is formed. Note that the developing device 5
A voltage is applied to the inner developing roller 5a by a developing bias power source (not shown) in order to obtain an optimum developing potential.

On the other hand, the transfer paper 15 placed in the paper feed cassette is fed by the MM roller 6, aligned with the image on the photoreceptor 1 by the registration rollers 17, and then conveyed to the transfer section. In the transfer section, the toner image is transferred onto a transfer paper 15 by a transfer/separator 6, and the transfer paper 15 is separated from the photoreceptor 1. Thereafter, the transfer paper 15 is conveyed to a heated fixing roller 18, where the toner image on the transfer paper 15 is thermally fixed to the transfer paper I5, and then discharged to a paper discharge tray 19.

On the other hand, after the photoreceptor 1 is transferred and separated, residual toner is removed by a cleaning device 7, and the photoreceptor 1 is ready for the next image forming cycle. Thereafter, by repeating this cycle, multiple copies are created.

Next, in the print mode, the photoconductor 1 is uniformly charged by the charger 2, and then exposed to light by the LED head 3 that emits light based on digital data from the outside, which causes an electrostatic charge to be generated on the photoconductor 1. A latent image is formed. The subsequent steps are the same as in the copy mode.

FIG. 3 is an external perspective view of the operating section, and shows the operating section main body 20.
is a seven segment display 21 that displays the number of copies etc.
, a start key 22 for starting the copy mode and print mode, and a numeric keypad 2 for inputting the number of copies, etc.
3. It is composed of a stop clear key 24 for clearing the set number and interrupting the transfer mode and print mode, and an input key 25 for setting the print mode.

FIG. 4 is an external perspective view of the LED head 3, in which 3a is a heat dissipating aluminum block that also serves as a mounting plate, 3b is a condensing beam transmitter, and 3c is a ceramic substrate, which is not shown above. A shift register IC chip with an LED chip driver and its peripheral passive element chips are assembled.

3d is a temperature detector, and its contact closes when the temperature of the detection part exceeds an arbitrary temperature. Further, 3e is a power supply line and a control signal line.

FIG. 1 is a schematic control block diagram of one embodiment, in which the operation section 20 transmits each input information to the main control section 30. It also receives display information from the main control section 30 and displays the information on the seven segment display 21.

The main control unit 30 controls the entire system of the electrophotographic apparatus, and includes a ROM in which a sequence program is stored.
30 b, RAM 30 G for temporarily storing necessary data on the sequence, I10 element 30 d for interfacing with other control units, and C for controlling these.
It is composed of a PU (microcomputer) 30a and the like.

Reference numeral 31 denotes a motor control unit that controls a DC servo motor (Ml) 32 for driving the scanner IO and a DC servo motor (M2) 33 for driving the photoreceptor 1. This control unit includes PLL control units 31b and 31c that perform PLL control of each of the motors 32 and 33, each motor 32,
Drivers 31d and 31e that supply control current to 33, and RAM and R that control the entire motor control section 31.
OM.

It is composed of a CPU 31a (1-chip microcomputer) with a built-in timer, Ilo, etc. Then, based on the mode information transmitted from the main control section 30, the CPU 31a inputs speed reference signals of the respective motors 32 and 33 to the PLL control sections 31b and 31C. The PLL control units 31b and 31G compare the output of the low-return encoder 34.35, which is mechanically connected to each motor 32.33 and generates pulses synchronized with the rotational speed of the motor, with the speed reference signal, and determine whether the error is zero. control so that

Therefore, by changing this speed reference signal, the rotational speed of each motor 32, 33 can be changed arbitrarily.

36 is a process control unit that controls units related to image formation, and is a C
It is composed of a PU (one-chip microcomputer) 36a, a driver array 36b, and the like. Then, a multi-bit control signal is generated based on the mode information transmitted from the main controller 30, and a high voltage power supply 37 and a developing bias power supply 3 are generated.
8. Send to process control unit such as lamp regulator 39. Each process control unit outputs an output arbitrarily set in advance based on a plurality of bits of control signals.

A memory section 40 stores print data in the print mode, and is composed of a dynamic RAM 40a and a gate array 40b that controls data input/output. 4
1 is an LED head control unit, and the LED in high speed mode
It is composed of an LED controller 41a that controls the head 3 and an LED controller 41b that controls the LED head 3 in the low speed mode. In this control unit, when the temperature detector 3d detects a preset arbitrary temperature, the print writing speed is reduced by receiving the signal and switching the LED head control circuit from the LED controller 41a to the LED controller 41b. At the same time, the signal is sent to the main control section 30, and the main control section 30 sends control signals for changing the photoreceptor speed, scanner scanning speed, and image forming conditions to the motor control section 31 and the process control section 36.

The motor control unit 31 and the process control unit 36 control the DC servo motors 32 .
33 and the process unit control output to adapt the control of the entire system to the change in print writing speed.

FIG. 5 is a main control flowchart of one embodiment, and the following description will be made according to the flow.

When a power switch (not shown) is turned on, a program stored in the ROM 3Qb in the main control section 30 starts. First, an initial set subflow for performing initial settings necessary for the copying operation is executed (5-1), and further process control during standby is performed (5-2). Next, check whether the start key 22 has been input or not.
3) If the determination result is N, the process returns immediately before the standby process control subflow (5-2). If the judgment result is Y,
Proceed to the next step and determine whether the print mode key 25 is pressed manually (5-4), print mode key 2
If 5 is not input (N at 5-4), execute the copy mode process below.

First, execute the copy mode set subflow that sets various conditions such as scanning and photoreceptor speed, high voltage power output, and bias power output necessary to execute the copy mode process (5-5), and then control the copy mode process. Execute the copy mode process control subflow 5-6) and move on to the next step. In the next step, it is determined whether the copy mode has ended (5-7), and if the determination result is N, the process returns to immediately before the copy process control subflow (5-6). If the judgment result is Y, the process returns to immediately before the standby process control subflow (5-2) and the next start key 2 is pressed.
2 input waiting state.

Further, in the print mode key manual determination flow (5-4), if the determination result is Y, that is, the print mode key 25 is input, the print mode process is executed below.

First, execute the print mode set subflow that sets various conditions such as scanning, photoconductor speed, high voltage power output, and bias power output necessary to execute the print mode process.
8), then determine the output of the temperature detector 3d (5-9)
. If the determination result is N, that is, if the temperature of the detection unit is below a predetermined value, then the LED head high-speed control subflow is executed (5-10), and the LED head 3 is controlled in the high-speed mode. Next, a high-speed mode set subflow is executed to set various conditions necessary for executing the print mode process in the high-speed mode (5-11), and the process moves to the next step. Also, in determining the output of the temperature detector 3d (5-9
), if the determination result is Y, that is, if the temperature of the detection unit is above a predetermined value, then the LED head low speed control subflow is executed (5-12), and the LED head 3 is controlled in the low speed mode. Next, the low-speed mode set subflow is executed to set various conditions necessary for executing the print mode process in the low-speed mode (5-13), and the process moves to the next step. In the next step, the printing process control is executed (5-14), and it is further determined whether the printing mode has ended (5-15). If the determination result is N, the determination flow of the temperature detector 3d (5-9) is performed. ) to return to the previous position. Further, if the determination result is Y, the process returns to immediately before the standby process control subflow (5-2), and the next start key 2 is pressed.
It enters the state of waiting for the input of 2.

Note that the control means described in the claims is constituted by the main control section 30, the motor control section 31, and the process control section 36.

〔Effect of the invention〕

As explained above, according to the present invention, the temperature of the LED head is detected and the photoreceptor speed and image forming conditions are switched based on the output to prevent the temperature of the LED head from rising excessively, so that printing can be interrupted. Therefore, it is possible to provide an electrophotographic apparatus that can reduce a decrease in print processing speed without causing any problems.

[Brief explanation of drawings]

Fig. 1 is a control block diagram of an embodiment of an electrophotographic apparatus according to the present invention, Fig. 2 is a configuration diagram of the electrophotographic apparatus, Fig. 3 is an external perspective view of the operating section, and Fig. 4 is an external external perspective view of the LED head. FIG. 5 is a control flowchart. 3... LED head, 30... Main control unit, 31...
- Motor control section, 36... process control section.

Claims (1)

[Claims] In an electrophotographic apparatus equipped with an LED head that performs optical writing in a print mode, in addition to an illumination lamp that illuminates the document in the copy mode, the LED head is equipped with a temperature detector that detects the temperature of the LED head, and the temperature detector 1. An electrophotographic apparatus characterized in that the main body includes a control means for switching a photoreceptor speed and image forming conditions in a print mode based on an output signal of the electrophotographic apparatus.