JPS61290466A - Image forming device - Google Patents

Abstract

PURPOSE:To increase the number of copied sheets per unit time of normal original copying by increasing the copying speed of a normal original faster than a speed for recording information except the original by using a liquid crystal microshutter array. CONSTITUTION:A copying machine is provided with a normal original copying device using an illuminating light source 4 and a device for recording information except the original through the liquid crystal microshutter array 42 and a short focus lens array 43. At the recording of the information except the original, the light source 4 is turned off and a photosensitive drum 1 is rotated at low speed under the consideration of the transmissibility of the liquid crystal to record the information. At the copying of a normal original, the light source 41 is turned off and the drum 1 is rotated at high speed by a signal outputted from a prescribed controller to copy the original. Consequently, the number of copied sheets per unit time of normal original copying can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus having a document quality information recording means such as a liquid crystal shutter or a tar array.

[Background of the invention]

FIG. 4 shows an example of an electrophotographic copying apparatus having document quality information recording means. This has a light source 20 and a liquid crystal micro shutter array 21 attached to one side of a movable document table 22. During normal copying, the document table 22 moves in synchronization with the rotation of the photosensitive drum 1, and first moves in the direction of the arrow. Photosensitive drum 1 that rotates.

The document 3 is uniformly charged by the charger 2, and then illuminated with a lamp 4 to form a latent image on the photosensitive drum 1 through the short focus lens array 5. The latent image is developed, while the transfer sheet 10 is conveyed through guides 11 and 13 by driving the paper feed roller 9 and registration roller 12, and the toner developed image is transferred by the charger 7. . After the transfer, the transfer sheet is peeled off from the photosensitive drum by a separation belt 14, a conveyance heald 15, and a fixing paper passes through an id 17 and is fixed by a fixing device 16. Further, residual toner on the photoreceptor is removed by a cleaning blade 8.

Also, when recording information outside the origin, the document table 22 is moved,
The liquid crystal microshaft array ztt is aligned with the short fi point lens array 5, and a drive signal is inputted from the liquid crystal shutter drive circuit to the nuclear fern and tar array 21 to form a latent image of original quality information on the photosensitive drum 1. A toner image of original document information is fixed on the transfer sheet using the same process as described above. At this time, the movement of the document table 22 is stopped and the light of the run f4 is turned off.

By the way, the gross speed in an electrophotographic copying apparatus having such a document quality information recording means is the same both when copying a document and when recording document quality information, and is caused by the transmittance of the liquid crystal microshape and tar array. The process speed was determined based on the document quality information recording means in view of the lack of light quantity and the delay in response time of the liquid crystal microshape and tar array.

Therefore, there is a problem that the process speed during normal original copying is slow and the number of copies is small.

The response time of the LCD microshape and tar array (
The relationship between t) and process speed (ν,) is as follows, where t=1ms, N=10 (bel), vp=10
0 wm/s, and considering the paper spacing, the number of copies is about 17 to 18 sheets/minute for A4 size, and N
= 46 (bells), it will be around 10 sheets/minute for A4 size.

On the other hand, the amount of light on the photosensitive drum is determined by the amount of light from the light source, the transmission efficiency of the short focus lens array, etc., and the transmittance of the liquid crystal (Figure 46).
The maximum transmittance of liquid crystal is determined by K, and the maximum transmittance of liquid crystal is about 15 to 20%. And the sensitivity of the photosensitive drum is 0.8μJ/
Using an OPC photoreceptor of about cm2, the process speed ν is around 401/1 at &f8 go, 10 pels, and around 25 k/s at 16 bells, and only about 7 sheets/min and 4 sheets/min, respectively, for A4 size. It won't happen. - [Object of the Invention] The present invention has been devised to solve these conventional problems, and it has been made to improve the process speed when copying originals,
The object of the present invention is to provide an image forming apparatus that can increase the process speed during normal copying of a document and increase the number of copies by changing the process speed when recording document quality information. be.

[Summary of the invention]

The image forming apparatus according to the present invention has different exposure means,
In an image forming apparatus that forms a latent image on an image carrier by exposing the image carrier with these exposure means,
The present invention is characterized in that a switching means is provided for switching the process speed in the latent image forming step to different speeds depending on the exposure means.

[Embodiments of the invention]

The present invention will be explained in detail below based on embodiments shown in the drawings.

FIG. 1 shows a block diagram of a process speed switching means in which the present invention is applied to a copying apparatus with a moving document table as shown in FIG.

In this original platen movable copying apparatus, an original platen glass 22, a photosensitive drum 1, a paper feed roller 9, a registration roller 12, a fixing roller of a fixing device 16, etc. are connected to a single motor 30 via a transmission means such as a gear (not shown). It is driven by The rotation of this motor 30 is controlled by a motor drive circuit 31. Reference numeral 32 denotes a sequence controller that manually inputs speed data and on-on motion f'14 to the motor drive circuit 31. When normal document copying is selected, a motor speed increase signal is input to the motor drive circuit 31 to increase the motor 30. When the recording of non-document information is selected, a motor deceleration signal is input to the motor drive circuit 31 to rotate the motor 3° at a low speed. The motor deceleration signal from the sequence controller 32 is used to move the document table 22 so that the liquid crystal microshaft array 21 and the short focus lens array 5 are aligned, and to fix the document table 22 at the minus number position. The motor speed increase signal is output when the document table 22 is at a position other than the motor deceleration output position.

Next, the operation of the copying apparatus according to this embodiment will be explained based on the flowchart shown in FIG.

When recording original quality information, first, the document table 22 is moved to a position where the liquid crystal microshape, the tar array 21, and the short focal length lens array 5 coincide with each other, and then fixed. Original table 22
When it is fixed at this non-document information recording position, a motor deceleration signal is output, the document illumination light source 4 is turned off, and the liquid crystal microshape and light source 20 of the tar array 21 are turned on. Then, the motor 30 is controlled to rotate at a low speed by the motor drive circuit 31, and the photosensitive drum 1 etc. are rotated at a low speed, and document quality information is exposed onto the photosensitive drum 1 by the liquid crystal microshape and the tar array 21. A fixed toner image of original information is formed on the transfer sheet 10 through the same latent image forming process as in the case of FIG.

On the other hand, when copying a document, release the document table 22 from the non-document information recording position, set the document on the document table 22, and press the copy button.
A motor speed increase signal is output from the , and the document table 22 , photosensitive drum 1 , etc. are driven at high speed, and the document exposure light is imaged on the photosensitive drum 1 to form a latent image, which is then transferred onto the transfer sheet 10 . A fixed toner image of the original image is formed.

As described above, according to this embodiment, the process speeds for recording the original quality information and for copying the original are changed, and the process speed when copying the original is made faster and more precise. The effect of increasing the number of copies per unit time can be obtained.

In this embodiment, a liquid crystal microshape, a tar array, and other non-document information recording means are installed at one end of the movable document table. However, as shown in FIG. , a liquid crystal shutter array 42, and a short focal length lens array 43 may be attached to record original quality information.

Also, the photosensitive drum 1, paper feed row 29, registration roller 1
Although the second drive motor 30 is driven by one drive motor 30, it may be driven by a plurality of motors.

〔Effect of the invention〕

As described above, according to the present invention, by making the image forming process speed of the original image faster than the image forming process speed of the original quality information, it is possible to increase the number of copies per unit time when copying the original, and also increase the number of copies per unit time when copying the original. You can get high quality images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the process speed control means of the image forming apparatus according to the present invention, and FIG. 2 is a flow chart explaining the operation of the image forming apparatus according to the present invention.
FIG. 3 is a schematic diagram of a copying device with a movable document table that can effectively implement the present invention, FIGS. 4 and 5 are schematic diagrams showing conventional copying devices with a movable document table, and FIG. FIG. 3 is a diagram showing the relationship between rate and time. 1: Photosensitive drum, 2, 7: Charger, 3: Document,
4: Lamp, 5.43: Short focus lens array, 6: Developer, 8: Cleaning punto 9
．． 9: Paper feed a-ra, 10: Transfer sheet, 11.1
3: ID, 12: Nostro roller, 14: Separation belt, 15: Conveyor belt, 16: Fixing device,
17 Two paper guides, 20.41: Light source, 21.42: Liquid Jit microshi, tar array, 22
: Original table, 30: Motor, 31: Motor drive circuit, 32 Nijiken controller.

Claims (1)

[Claims] In an image forming apparatus that has different exposure means and forms a latent image on the image carrier by exposing the image carrier with these exposure means, the process speed in the latent image forming step is selected depending on the exposure means. An image forming apparatus characterized in that it is provided with a switching means for switching to.