JPS63125956A - Photosensitive body temperature controller - Google Patents

Abstract

PURPOSE:To prevent a temperature sensor from malfunctioning at the time of temperature detection by rotating a photosensitive drum at slower speed in copying stand-by mode than in copying operation so that the photosensitive drum is not heated locally by a fixing heater. CONSTITUTION:When the copying operation is performed, a signal E1 is inputted to a control means C and a motor M rotates the photosensitive drum 31 at the speed of 30 turns per minute. When a copying machine main body 11 finishes copying and afterward processes, a signal E2 is inputted to the control means C and the motor M rotates the photosensitive drum 31 at the speed of one turn per minute for a period until the next start of copying operation, i.e. in copying stand-by mode. Here, a heat source lamp H2 is provided on the left side of the photosensitive drum 31, so the temperature of the photosensitive drum 31 rises by its heat radiation, the rotation is maintained even in the copying stand-by mode, so the photosensitive drum 31 is never heated locally. The temperature sensor 3, therefore, detects the temperature of the photosensitive drum 31 without malfunctioning. An electric heater 11, on the other hand, holds the temperature of the photosensitive drum 31 at a specific value.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a temperature control device for a photoreceptor used in an electrophotographic copying machine.

(b) Conventional technology Some of the photoconductors on the surface of the photoconductor drum in copiers have sensitivity that changes depending on the temperature. The temperature of the body is detected by a temperature sensor and the energization of the electric heater is controlled to keep the temperature almost constant (for example, 36 to 40 degrees Celsius for selenium arsenic photoconductors and 45 to 50 degrees Celsius for amorphous silicon photoconductors). (For example, see Utility Model Application Publication No. 61-99159@). If the temperature sensor that detects the temperature of the photoconductor is installed outside the photoconductor drum, the photoconductor and sensor cannot come into contact and the detection results will be inaccurate, so recently, it has been fixed inside the photoconductor drum. It is becoming more and more common to have them installed.

(c) Problems to be Solved by the Invention Incidentally, in an electronic copying machine, in order to heat and fix the transfer paper onto which the toner image has been developed and transferred on the photoreceptor drum, a fixing heater that generates a large amount of heat is attached to the photoreceptor drum. are installed side by side. Therefore, if the photoconductor drum is stopped while the temperature sensor provided inside the photoconductor drum is close to and facing the fixing heater, the temperature sensor will
Since the photoreceptor heater is controlled by detecting the local temperature of the photoreceptor heated by the fixing heater, there is a problem in that the temperature of the entire photoreceptor is not maintained at a predetermined value.

This invention was made in consideration of these circumstances,
In order to prevent the photosensitive drum from being locally heated by the fixing heater, the photosensitive drum is rotated at a lower speed during copying standby than during copying, thereby preventing malfunctions in temperature detection by the temperature sensor.

(d) Means for Solving Problems This invention includes an electric heater that heats a rotating photoreceptor drum, a temperature sensor that is fixed near the inner peripheral surface of the photoreceptor drum and detects the temperature of the photoreceptor; In a photoreceptor temperature control device equipped with a control means for controlling energization to an electric heater based on the output of the temperature sensor, the photoreceptor drum is rotated at a predetermined speed during copying, and the photoreceptor drum is rotated at the predetermined speed during copy standby. This is a photoconductor temperature control device characterized by comprising a control means for rotating the photoconductor at a speed lower than that of the photoreceptor.

The rotational speed of the photosensitive drum during copying standby may be 1/10 or less of the rotational speed during copying, for example, about 1 rotation per minute.

(E) Operation Since the photoreceptor drum continues to rotate even during copying standby, even if another heat source is installed alongside the photoreceptor drum, the photoreceptor drum will not be locally heated by that heat source.

Therefore, the temperature sensor is prevented from detecting an incorrect temperature.

(f) Examples Hereinafter, the present invention will be described in detail based on examples shown in the drawings. Note that this invention is not limited to this.

FIG. 1 is an explanatory diagram of the configuration of a copying machine showing an embodiment of the present invention.
, an exposure lamp 21, reflecting mirrors 22, 23 .
24, a lens 25, and a reflecting mirror 26.
By moving 23 and 24 in the direction of arrow A, the original can be scanned and exposed sequentially. The exposure lamp 21 and the flat reflecting mirror 22 move together, and the flat reflecting mirrors 23 and 24 also move together, and the moving speed of the former is set to be twice that of the latter. There is. A copying processing system 3 is provided below the optical system 2 and includes a photosensitive drum 31 rotating in the direction of arrow B, a charging charger 33, a developing device 34, a transfer charger 35, a separation charger 36, and a cleaner 37. An electrostatic latent image is formed by irradiating the surface of the photoreceptor drum 31, which is uniformly charged by the charger 33, with light reflected from the document plate, and this electrostatic latent image is converted into toner by the developing device 34. The toner image is visualized into an image, and the toner image can be transferred onto the copy paper P by the transfer charger 35. The copy paper feeding system 4 includes a paper feeding roller 41, a paper feeding path 42, and a registration roller 4.
3. It is composed of a conveyor belt 44, a fixing device 45, and an ejection roller 46. By driving the paper feed roller 41, copy paper P is fed one by one from the paper feed cassette 12, and by the registration roller 43, The copy paper P is conveyed in synchronization with the photosensitive drum 31, and the copy paper P after the toner image transfer is conveyed to the fixing device 45 by the conveyance belt 44.
After the toner image is fixed, the copy paper P can be discharged onto the tray 13 by the discharge roller 46. Further, reference numeral 10 denotes a document holder which is attached so as to be movable downward by a hinge mechanism (not shown) to cover the upper surface of the document table 1.

Furthermore, H1 is an electric heater provided on the inner peripheral surface of the photoreceptor drum 31, S is a temperature sensor fixed to the inner peripheral surface of the photoreceptor drum 31, and H2 is a heat source lamp of the fixing device 45.

FIG. 2 shows a control 1' for controlling the rotation of the photosensitive drum 31 in FIG.
1 is a block diagram of a control circuit; 1. El is a copy start signal output from the copying machine main body 11 when copying is started;
E2 is the copying machine main body 11 at the end of copying and subsequent processing.
C is a motor speed control means, and M is a motor for rotating the photosensitive drum 31.

In such a configuration, when the copying machine main body 11 performs a copying operation, the signal E1 shown in FIG. 2 is input to the control means C, and the motor M rotates the photosensitive drum 31 at a speed of 300 revolutions per minute. When the copying machine main body 11 finishes copying and subsequent processing, a signal E2 is input to the control means C, and the motor M rotates the photoreceptor drum 31 at one revolution per minute until the start of the next copy, that is, during copy standby. Rotate at speed.

By the way, as shown in FIG. 1, since the heat source lamp H2 is installed on the left side of the photoreceptor drum 31, the temperature of the photoreceptor drum 31 rises due to its heat radiation, but as described above, the rotation continues even during copying standby. Therefore, the photoreceptor drum 31 is not locally heated. Therefore, since the temperature sensor 3 detects the temperature of the photoreceptor drum 31 without malfunctioning, the electric heater H1 can maintain the temperature of the photoreceptor drum 31 at a predetermined value.

(G) Effects of the Invention According to the present invention, the photoreceptor drum is not locally heated by the fixing heater and malfunction of the temperature sensor is prevented, so that the photoreceptor drum is maintained at a predetermined temperature.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the construction of a copying machine showing an embodiment of the present invention, and FIG. 2 is a block diagram of a control circuit for controlling the rotation of the photosensitive drum shown in FIG. El...Copying instruction signal, E2...Copying standby instruction signal, C...
Motor speed control means, M...Motor, 31...Photosensitive drum.

Claims (1)

[Claims] 1. An electric heater that heats the rotating photoreceptor drum, a temperature sensor that is fixed near the inner peripheral surface of the photoreceptor drum and detects the temperature of the photoreceptor, and the output of the temperature sensor controls the power supply to the electric heater. The photoreceptor temperature control device includes a control means for rotating the photoreceptor drum at a predetermined speed during copying, and rotating the photoreceptor drum at a speed lower than the predetermined speed during copying standby. Characteristic photoconductor temperature control device.