JPH0475939A - Recording paper size detecting method for electrophotography device - Google Patents

Abstract

PURPOSE:To correctly detect the size of recording paper by detecting the width of the recording paper fed from a manual feeder with outputs of multiple sensors, and detecting the length of the recording paper with the feed quantity of the recording paper until the outputs of the sensors are changed. CONSTITUTION:The width of the recording paper fed from a manual feeder 15 is detected by outputs of multiple sensors 17a-17c, and the length of the recording paper is detected by the feed quantity of the recording paper until the outputs of the sensors 17a-17c are changed. The size of the recording paper is detected by the detected width and length of the recording paper.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to electrophotography that detects the size of recording paper set in a manual feeder used in electrophotographic devices such as LED plotters, laser printers, and liquid crystal printers. The present invention relates to a recording paper size detection method using a method.

[Prior Art] Electrophotographic apparatuses such as LED plotters and laser printers are generally equipped with a manual feeder as well as an automatic sheet feeder (hereinafter referred to as ASF).

When ASF is used, the size of the recording paper is set, for example, by operating a key panel, so once the size of the recording paper is set, the exposure range, that is, the drawing area on the photosensitive drum is determined. Thereby, it is possible to perform recording that matches the recording paper size.

[Problems to be Solved by the Invention] However, when feeding recording paper using a manual feeder, the recording paper size is not determined at all, or the recording paper size is determined only by the width of the recording paper. For example, if A4 size paper is supplied horizontally,
Indistinguishable from A3 size. Further, even if recording paper of an intermediate size is supplied, the size of the recording paper cannot be determined. As a result, the drawing area cannot be set correctly, resulting in wasted exposure and toner adhering to areas where the paper is not fed onto the photosensitive drum, increasing toner consumption and causing problems with the transfer and peeling devices. Problems such as staining with toner occur.

The present invention has been made in view of such problems, and provides a recording paper size detection method for an electrophotographic apparatus that can correctly determine the size of recording paper even when the recording paper is fed from a manual feeder. The purpose is to provide.

[Means for Solving the Problems] A recording paper size detection method for an electrophotographic apparatus according to the present invention includes:
The width of the recording paper set in the manual feeder is detected by the output of a plurality of sensors, and the length of the recording paper is detected by the amount of feeding of the recording paper until the output of the sensor changes, and these detected values are detected. The size of the recording paper is determined based on the width and length of the recording paper.

[Operation] According to the present invention, the width of the recording paper fed from the manual feeder is detected by the outputs of a plurality of sensors, and the length of the recording paper is determined by the feeding amount of the recording paper until the output of the sensor changes. Since the size of the recording paper is detected, the size of the recording paper can be detected based on the detected width and length of the recording paper.

Therefore, even when feeding recording paper from a manual feeder, the size of the recording paper can be correctly determined, and the drawing area of the photosensitive drum, etc. can be set correctly.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of an LED plotter according to an embodiment of the present invention.

This LED plotter is composed of a plotter main body 1 and an ASF 2.

A photosensitive drum 3 is provided inside the plotter main body 1 and rotates in the direction of the arrow in the figure during recording. The following elements necessary for the electrophotographic process are arranged around the photosensitive drum 3.

First, a main charger 4 that uniformly charges the photosensitive drum 3 to, for example, 800 to 1000V is arranged at the most upstream side in the rotational direction of the photosensitive drum 3. At a downstream position of the main charger 4, there is an LED head 5 comprising a light emitting diode (LED) array that selectively exposes the photosensitive drum 3 charged by the main charger 4 to light according to recorded data to form an electrostatic latent image. , and a SELFOC lens 6 that images the light from the LED head 5 onto the photosensitive drum 3. At the downstream position of the LED head 5,
A developing device 7 is arranged to supply toner to the photosensitive drum 3 and visualize the electrostatic latent image as a toner image. A transfer device 8 is disposed downstream of the developing device 7 and supplies electric charge for transferring the toner image formed by the developing device 7 onto recording paper. A peeler 9 is disposed downstream of the transfer device 8 and supplies a charge to peel the recording paper from the photosensitive drum 3. A cleaning device 10 that removes toner adhering to the photosensitive drum 3 and cleans the surface of the photosensitive drum 3 is disposed further downstream of the peeling device 8 . Further, at a downstream position of the cleaner 10, that is, at a position immediately upstream of the main charger 4, a static elimination lamp 11 for removing residual charges on the photosensitive drum 3 is arranged. A fixing device 12 is arranged downstream of the peeling device 9 in the paper conveyance path. A feed roller 13 is arranged downstream of the fixing device 11,
Furthermore, a stacker 14 for holding recorded recording paper is arranged at a downstream position.

On the other hand, the plotter main body 1 is provided with a manual feeder 15. This manual feeder 15 includes a tray 16 that guides the recording paper, and a plurality of sensors 17 a * 17 b + for detecting that recording paper is set in the manual feed mite 5 and the width of the set recording paper.
17c, a paper feed roller 18 and a conveyance roller 19 for taking recording paper into the plotter main body 1.

FIG. 2 shows the positional relationship of the sensors 17 al 17 b and 17 c when viewed from the arrow A in FIG. 1. That is, the sensors 17a to 17c are arranged in a straight line at the most downstream position in the recording paper moving direction in the recording paper setting range. The sensor 17a is located at the end in the width direction within the setting range for AO size recording paper, the sensor 17b is located at the end in the width direction within the setting range for A1 size recording paper, and the sensor 17c is located at the end in the width direction within the setting range for A1 size recording paper. It is located at the end in the width direction within the setting range for A3 size recording paper.

On the other hand, ASF2 has four cassettes 21, 22, and 23.
．． 24 is installed. These cassettes) 21, 22,
The paper stored in 23 and 24 is fed to paper feed rollers 25 and 24, respectively.
26, 27, and 28, and is conveyed to the plotter main body 1 along a route indicated by a two-dot chain arrow in the figure.

The recording paper fed from the ASF 2 and the manual feeder 15 reaches the transfer device 8 via a paper jam detection sensor 29 and a conveyance roller 30.

Next, a procedure for detecting the recording paper size of the manual feeder 15 in the LED plotter according to the present embodiment configured as described above will be described.

FIG. 3 is a flowchart showing the procedure for detecting the recording paper size.

When the recording operation is started, if the outputs of the sensors 17a to 17c of the manual feeder 15 are all off, that is, the presence of recording paper is not detected (Sl), no recording paper is set in the manual feeder 15. 3.
2) Start ASF2 (S3).

On the other hand, when recording paper is set in the manual feeder 15, as is clear from FIG.
As shown in Table 1 below, the outputs of 17c to 17c show three types of output depending on the size of the recording paper.

Table 1 Therefore, the 3-bit output from the sensors 17a to 17c is detected (S4), and if the sensor output indicates "7", an AO size drawing area is set (S5).
. Also, if the sensor output shows “3”, Al
(Portrait) or A2 (Horizontal) size drawing width is set (S, l), and if the sensor output indicates "1", A3 (Portrait) or A4 (Horizontal) size drawing The width is set (S7).

If the drawing width is set to A1 or A2 size, the second
The recording paper is fed by a distance Ll shown in the figure (S8), and it is determined whether any of the sensors 17a to 17c are turned off (Sl). Then, if all sensor outputs are off, A2 size (S, O), otherwise A1 size.
Set the drawing length as the size (S, , ).

Furthermore, when the drawing width is set to A3 or A4 size, the recording paper is fed by the distance L2 shown in Fig. 2 (S12).
, it is determined whether all of the sensors 17a to 17c are turned off (Sss). Then, if all sensor outputs are off, the drawing length is set to A4 size (S14), otherwise, the drawing length is set to A3 size (S re).

By performing these steps, three sensors 1
7a to 17c only check whether recording paper is set in the manual feeder 15 and whether the set recording paper is A
It is possible to detect which size among O-A4 sizes.

Incidentally, each of the sensors 17a to f7c is shown in FIG.
When divided into two sensors 41 and 42 as shown in a), when the recording paper is set at an angle, as the recording paper moves, which sensor 41
, 42 are also on → either sensor is off → both sensors 41 and 42 are off, so the inclination θ of the recording paper is determined based on the period during which either sensor output is off and the distance between the sensors. It can be calculated. Then, based on this inclination θ, the bitmap data can be corrected so that it is parallel to the recording paper.

Further, in the above embodiment, the recording paper size detection sensors 17a to 17c of the manual feeder 15 are arranged in a straight line at the most downstream position in the recording paper moving direction in the recording paper setting range, but for example, as shown in FIG. AO, A2. It may be arranged at the most upstream position in the recording paper movement direction in each A4 size recording paper setting range. In this case,
As shown in FIG. 6, since the distance between the sensors 17a to 17c becomes longer, the size of the tray 16 becomes thicker, but the length of the recording paper can be reduced by feeding the recording paper a small distance. This method has the advantage that the paper size can be detected and the time required to detect the recording paper size is short.

[Effects of the Invention] As described above, according to the present invention, the width of the recording paper fed from the manual feeder is detected by the outputs of a plurality of sensors, and the width of the recording paper is detected until the output of the sensor changes. Since the length of the recording paper is detected based on the feed amount, the size of the recording paper can be accurately detected based on the detected width and length of the recording paper.

Therefore, even when feeding recording paper from a manual feeder, the size of the recording paper can be correctly determined, and the drawing area of the photosensitive drum, etc. can be set correctly.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an LED plotter according to a first embodiment of the present invention, FIG. 2 is a schematic diagram showing the position of a recording paper size sensor in the same plotter, and FIG. 3 is a diagram showing recording paper size detection in the same plotter. A flowchart showing the procedure, FIG. 4 is a schematic diagram showing a recording paper size detection sensor in an LED plotter according to the second embodiment of the present invention, and FIGS. 5 and 6 are according to the third embodiment of the present invention. FIG. 3 is a schematic diagram showing the positions of recording paper size detection sensors in such an LED plotter. 1; Plotter body, 2; ASF (auto sheet feeder), 3; Photosensitive drum, 4; Main charger, 5; LE
D head, 6; Selfoc lens, 7; developer, 8;
Transfer device, 9; Peeling device, 10; Cleaning device, 11; Static elimination lamp, 12; Fixing device, 13: Feed roller, 14; Stacker,
15; manual feeder, 16; tray, 17a to 17c
, 29t41.42; sensor, 18, 25-28; paper feed roller, 19, 30; transport roller, set 21-24;

Claims (1)

[Claims] (1) Detecting the width of the recording paper set in a manual feeder using the outputs of a plurality of sensors, and detecting the length of the recording paper based on the feeding amount of the recording paper until the output of the sensor changes; A recording paper size detection method for an electrophotographic apparatus, characterized in that the size of the recording paper is determined based on the detected width and length of the recording paper.