JPH05142881A - Copying machine - Google Patents

Abstract

PURPOSE:To solve underexposure in a high-speed mode when the high-speed mode is added to a copying machine with keeping the cooling relationship. CONSTITUTION:When a high-speed mode is selected through manipulation of a high-speed mode selection key 2, a voltage regulating circuit 3 is controlled by a control circuit 7, a voltage supplied to a halogen lamp 4 of a scanning optical system is raised as a whole and its upper limit is set higher than that in a normal mode. And when a measured temperature at an optical thermistor 5 becomes more than a predetermined value during copying in the high-speed mode, a copying mechanism 6 is controlled by the control circuit 7 so as to suspend the copying for the time being.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine in which a normal mode capable of copying at a normal copying speed and a high speed mode capable of copying at a higher copying speed can be selected.

[0002]

2. Description of the Related Art Conventionally, the copying speed of a copying machine is fixed and fixed for each model. However, recently, a copying machine with a high-speed mode has been proposed in which a high-speed mode selection key is separately provided and the copying speed can be increased by operating this high-speed mode selection key. The copying speed is increased by increasing the copying process speed (for example, the scanning speed of the scanning optical system, the rotation speed of the photosensitive drum, etc.) as compared with the normal mode of the copying speed.

[0003]

However, when the copying process speed is increased, especially when the rotation speed of the photosensitive drum is increased, the exposure amount becomes insufficient. Therefore, it is necessary to raise the supply voltage to the halogen lamp to raise the light amount of the halogen lamp, but simply raising it will cause insufficient cooling of the optical system and will not clear the safety standard. In particular, it is necessary to raise the cooling-related ability of the optical system, and as a result, it is necessary to review the basic design, and there is a risk that the model will be one rank higher in terms of cost.

For example, the exposure amount in the normal mode is as shown by P1 in FIG. 4 according to the exposure setting value, and the exposure setting value is the exposure setting value "4" for obtaining an appropriate exposure amount.
If the value is smaller than the above value, the exposure amount is decreased and the copy density is increased, and conversely, if the value is increased, the exposure amount is increased and the copy density is decreased. The voltage supplied to the lamp is designed to cool the optical system so that the temperature rise of the contact glass falls within the safety standard value during continuous copying with the upper limit value V1). In order to eliminate the shortage of the exposure amount in the high speed mode with respect to the exposure amount in the normal mode, it is necessary to raise the minimum, proper and maximum exposure amounts as a whole as shown in P2 of FIG. That is, the supply voltage to the halogen lamp is increased as a whole and the upper limit value is V2 (>
V1), which causes an exposure amount portion A having a maximum exposure amount X or more in the normal mode and insufficient cooling during continuous copying with the maximum exposure amount Y to clear the safety standard. It was not possible to do so, and it was necessary to review the cooling relationship. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a copying machine which can eliminate the shortage of the exposure amount in the high speed mode while maintaining the cooling relationship.

[0005]

According to the present invention, in order to achieve the above object, a high speed copying machine capable of selecting a normal mode having a normal copying speed and a high speed mode having a copying speed higher than the normal mode. In the mode, the voltage supplied to the halogen lamp of the scanning optical system is increased overall to set the upper limit value higher than that in the normal mode, and the temperature around the optical system or the photoconductor drum during copying in the high speed mode. Is a predetermined value or more, a mode control means for temporarily interrupting copying is provided. Specifically, the mode control means includes a voltage adjustment circuit for adjusting the supply voltage to the halogen lamp and a contact glass of the optical system. An optical thermistor that measures temperature and a voltage adjustment circuit based on mode selection, and a copy mechanism based on the temperature measured by the optical thermistor It is those containing a that control circuit.

[0006]

With this structure, the exposure amount in the high speed mode can be made larger than that in the normal mode without reviewing the cooling relation, and continuous copying at the maximum exposure amount is within the safety standard. Can be done.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, in order to keep the cooling relationship in the normal mode, the upper limit value of the voltage supplied to the halogen lamp of the scanning optical system in the high speed mode is set higher than that in the normal mode, and the maximum, proper, and minimum values are set. Although the exposure amount is also raised overall, when the temperature around the optical system or the photoconductor drum reaches or exceeds a predetermined value during copying in the high speed mode, copying is temporarily interrupted and cooling is performed for a predetermined period. is there. Specifically, it is configured as shown in FIG. 1, and 1 is an operation panel section in which a high speed mode selection key 2 for selecting a high speed mode together with a key for instructing the start of copying, the number of copies, etc. A voltage adjusting circuit that adjusts the voltage supplied to the halogen lamp 4 according to the exposure amount setting value so that the proper and maximum exposure amount can be obtained. The minimum, proper, and maximum exposure amounts suitable for the normal mode and the high-speed mode, respectively. Is controlled by a control circuit described later so that Reference numeral 5 is an optical system thermistor for measuring the temperature of the contact glass on which the original is placed, 6 is a copying mechanism which is composed of a scanning optical system, a photosensitive drum, etc., and whose copying operation is controlled by a control circuit described later, 7 Controls the voltage adjusting circuit 3 based on the operation of the high-speed mode selection key 2 and the copying mechanism 6 based on the temperature measured by the optical system thermistor 5.
This control circuit 7 controls the voltage supplied to the halogen lamp 4 to be higher than that in the normal mode when the high-speed mode is selected by operating the high-speed mode selection key 2. The voltage adjusting circuit 3 is controlled so as to adjust the voltage from V1 to V2, and when the temperature measured by the optical system thermistor 5 becomes a predetermined value or more during copying in the high speed mode, the copying is temporarily stopped, that is, The copying mechanism 6 is controlled so that only the cooling fan is rotationally driven to cool for a predetermined period. Here, 8 is a memory (ROM in this case) in which a control program of the CPU used as a control circuit is stored. With such a configuration, the voltage exceeding the upper limit value V1 is not supplied to the halogen lamp 4 by the control circuit 7 in the normal mode, so that continuous copying with the maximum exposure amount X has a large number of copies. It will be done without interruption within safety standards. Then, in the high speed mode, the control circuit 7 increases the exposure amount and the upper limit value of the voltage supplied to the halogen lamp 4 is higher than V1.
Since it is set to 2, the continuous copying with the maximum exposure amount Y is automatically interrupted during the copying when the number of copying is large and automatically restarted after being cooled for a predetermined period so as to be within the safety standard. It will be done while repeating this.

2 and 3 are an external view and a longitudinal sectional view of a copying machine with a high-speed mode having such a mode control structure, and the copying mechanism 6 thereof is an original document placed on a contact glass 9. A scanning optical system 10 including a halogen lamp 4 for reading the data, an exposure unit 13 including a condenser lens 11 and a mirror 12, a photoconductor drum 14 on which a latent image is formed by the exposure unit 13, and the photoconductor drum. Developing unit 15 for developing the latent image on the photosensitive drum 14 and the developed photosensitive drum 14.
A transfer unit 19 including a transfer charger 18 for transferring the upper image onto a sheet sent from the sheet feed tray 16 or the sheet feed cassette 17, and a fixing unit 20 for fixing the transfer unit 19.
It is composed of a cooling fan (not shown) and the like. 2
A developing thermistor 1 is provided in the developing unit 15 and measures the temperature for controlling the amount of toner replenishment, and the optical system thermistor 5 is provided in the non-image area of the contact glass 9. In such a copying machine, first, in the normal mode in which the high-speed mode selection key 2 is not operated, the control circuit 7 drives the copying mechanism 6 at a normal copying process speed to perform copying at a normal copying speed. It will be. Then, in the high speed mode in which the high speed mode selection key 2 is operated, the control circuit 7 increases the copying process speed of the copying mechanism 6 and the light amount of the halogen lamp 4 to perform the copying at a high copying speed, in particular. In the continuous copying of a large number of sheets at the maximum exposure amount, the pattern of copying → interruption (cooling) → copying is performed. It should be noted that when the number of copies is small or continuous copying with a proper exposure amount that is normally used, it can be performed with almost no interruption. As described above, in the present embodiment, copying is interrupted on the basis of the temperature measured by the optical thermistor provided on the contact glass in the high speed mode, but it is provided at the developing unit to measure the temperature around the photosensitive drum. It may be performed based on the temperature measured by the developing thermistor.

[0009]

As described above, according to the present invention, during the copying in the high speed mode, the copying is temporarily interrupted to provide a cooling period. The high-speed mode can be added easily.

[Brief description of drawings]

FIG. 1 is a diagram showing a mode control configuration example for realizing the present invention.

FIG. 2 is a perspective view of a copying machine that implements it.

FIG. 3 is a schematic sectional view thereof.

FIG. 4 is a diagram showing exposure characteristics in the normal mode and the high speed mode.

[Explanation of symbols]

 2 High speed mode selection key 3 Voltage adjustment circuit 4 Halogen lamp 5 Optical system thermistor 6 Copying mechanism 7 Control circuit

Front page continuation (72) Inventor Hiroyuki Sakamoto 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Engineering Co., Ltd. In the company

Claims (2)

[Claims] 1. In a copying machine capable of selecting a normal mode of a normal copying speed and a high speed mode of a higher copying speed, a voltage supplied to a halogen lamp of a scanning optical system in the high speed mode is generally increased. The upper limit value is set higher than that in the normal mode, and mode control means is provided for temporarily interrupting the copying when the temperature around the optical system or the photosensitive drum becomes a predetermined value or more during copying in the high speed mode. Characteristic copier. 2. The mode control means controls a voltage adjusting circuit for adjusting a supply voltage to a halogen lamp, an optical system thermistor for measuring a temperature of a contact glass of an optical system, and a voltage adjusting circuit based on mode selection. The copying machine according to claim 1, further comprising a control circuit for controlling the copying mechanism based on the temperature measured by the optical system thermistor.