JPH02171260A - Electrophotographic printer - Google Patents

Abstract

PURPOSE:To obtain a longer LED head life and to inhibit the wasteful use of a toner by a method wherein only LED head data coincident with a printing area of printing paper is inputted to an LED head body, and only LED heads corresponding to the printing paper are emitted. CONSTITUTION:For example, a signal indicating A4-size printing paper is detected by a mechanism part 11 to be stored in a RAM 3 through a printing paper state input part 6. When printing data of B4-size paper having a line- direction width longer than that of the A4-size paper is received from a host device, an LED data generation part 5 makes LED head data B4-size data and inputs it to an LED head emission area setting circuit 7. However, with the detection of the A4-size, a CPU 1 reads a printing area setting time table 2a provided in a ROM 2 for setting a printing area for the A4-size and supplies to to a timer circuit 8. The timer circuit 8 counts the time to obtain LED head data coincident with the previously selected printing paper. The data is inputted to an LED head 52.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to electrophotographic printers.

<Prior art> The image forming process of an electrophotographic printer involves charging, LE
This is done in five steps: formation of an electrostatic latent image on the photosensitive drum by light irradiation called writing by the D head, phenomenon caused by toner, transfer of toner to printing paper, and fixation by heat and pressure.

FIG. 6 is a diagram schematically showing the relationship between the LED head and the photosensitive drum l. In this figure, the LED head body 5
2 has a light emitting section 52a which is a collection of light emitting elements, and when print data is received from a host device, an electrostatic latent image is formed on the photoreceptor drum 50 in accordance with the data. For example, when the host device sends data for the length of the print paper 2 in the row direction, the LED head main body 5
2 forms an electrostatic latent image with a width of L on the photosensitive drum 50. Toner is attached to this trailing width, and an image, ie, print data, is formed on the printing paper through the steps of transfer and heat fixing described above.

However, in conventional electrophotographic printers that can handle either multiple sheets of paper or continuous folded paper, even if the printing paper of width L2 in this figure is selected, this printing paper If data with a width that exceeds the width of L2 is sent regardless of the size of
Regardless of the selected printing paper, even if the data in the line direction exceeds the width of the printing paper, the LED head corresponding to the data for one line is lit.

<Problems to be Solved by the Invention> Printing on printing paper with a printing range smaller than the number of data in the row direction of the received print data naturally results in the data being discarded, and conventionally it has been difficult to replace the paper or print data from the host device. The process of retransmission is common in various printer devices.

However, in conventional electrophotographic printers, the LED head lights up regardless of the printing range of the printing paper as described above, so when the toner in the non-printing area outside the printing range, for example paper 1 in FIG. 6, is selected. The shaded areas of Ll and L3 are simply thrown away, which is a waste of toner, and lighting the LED head in the non-printing area outside the printing range is also a waste of lighting, which shortens the life of the LED head. There were also issues such as providing a shadow.

Means for Solving the Problems> The present invention is designed to reduce the lifespan of the LED hand and the wasteful use of toner, even if the received print data is also wasted as in the past, and solves this problem. Therefore, in electrophotographic printers that can handle multiple print sheets or continuous folded sheets and are equipped with a means to detect the size of the print sheets, print data can be transferred to any of the print sheets. When printing, the printing range of the printing paper is set by means for detecting the size of the printing paper, and when the print data in the line direction exceeds the printing range, the printing range is set by means consisting of a programmable interval timer circuit. The LED head was turned on only within the printing range, and the LED head was not turned on in a range beyond the set printing range.

Function> When receiving a signal indicating the size of printing paper from the mechanical section of the electrophotographic printer, the CPU of the control section executes the program RO.
Read the print range setting time table corresponding to the print paper size set as part of M, and send the result to LE.
Supplied to the programmable interval timer circuit of the D head lighting range setting circuit. This programmable interval timer circuit counts time with this input.

This counted output is a serial signal of the LED
The data is input to the AND circuit together with the head data and becomes input data to the LED head main body corresponding to the printing range of the printing paper. Therefore, only the LED head data that matches the printing range of the printing paper is input to the LED head main body, so that only the LED head corresponding to the printing paper is lit.

<Embodiment> An embodiment of the present invention will be described below based on the drawings from FIG. 1 to FIG. 5.

FIG. 3 is a side view showing a schematic configuration of an electrophotographic printer that can use both cut sheets and continuous folded sheets, and which is applied to the present invention.

In the figure, reference numeral 50 denotes a photoconductor drum whose surface is made of a photoconductor, which rotates in the direction of the arrow in the figure.
The surface charge is given by The photosensitive drum 50 is irradiated with light from the LED head main body 52 to form an electrostatic latent image.

Thereafter, this electrostatic latent image is made visible by the toner in the toner container 54 being attached by the developing device 53.

On the other hand, the cut sheet 56 stored in the fuser 55 is fed to the top of the sheet conveyance path by a roller 57 and conveyed.

The toner adhered on the photosensitive drum 50 is transferred onto this cut sheet by a transfer device 59. Thereafter, it is fixed by the fixing device 60 and discharged in the direction of arrow A. Furthermore, after the transfer has been completed, the photosensitive drum 50 has its surface charge removed by an eraser 61, residual toner is scraped off by a blade 62, and cleaned by a cleaner 63, returning to its original state and repeating this process.

What has been explained above is the same for the continuous folded paper 64, which is taken into the conveyance path 58 by the paper feed roller 57a and performs the same operation.

By the way, the cut paper 56 which is the printing paper of this electrophotographic printer has each size of A4, B4, and B5 in this embodiment, and the continuous folded paper 64 is connected to the conveyance path 58 by the cut paper 56.
Since this overlaps with the above, paper with widths of 15 inches and 16 inches can be used. As means for detecting the sizes of these printing papers, a control section (not shown) is informed by a continuously folded paper detection means 71 using a combination of light emitting and light receiving elements and a cut paper detection means 72 using a micro switch or the like.

FIGS. 4 and 5 are diagrams showing an example of means 72 for detecting the size of the cut sheet 56. FIG. In the figure, 72a is a guide roller, 72b is a paper guide, and MSI to MS3 are microswitches. By moving the paper guide 72b to the setting position for the paper size (A4, B4, B5), the guide roller 72a also moves and the micro switch M is moved.
SI to MS3 are pressed to notify the size of the cut sheet 56.

Next, setting of the lighting range of the LED head of the present invention will be explained.

Figure 1 shows L during the series of operations in Figures 3 and 4.
FIG. 3 is a block diagram of LED head lighting range setting control that focuses only on the control of the ED head.

In FIG. 1, CPUI is a general-purpose microprocessor that reads out the program ROM 2, decodes it, and executes it.

11 is a part of the mechanism of the electrophotographic printer explained in FIG. A data selection section that selects data according to the light emitting section and a drive circuit that drives the light emitting section are built-in.

Reference numeral 61 inputs signals from a mechanical section that is a means for detecting the size of cut paper or continuous folded paper shown in FIGS. 3 and 4, and a means for detecting the near end of paper (not shown). This is a printing paper state detection unit that notifies the unit 6 of the printing paper condition.

When the CPUI detects the state of the print paper from the print paper state input unit 6, it stores it in a predetermined location in the RAM 3. When print data is received from the host device through the interface circuit 4, it is stored in a predetermined location in the RAM 3.

Next, the LED head data creation section 5 stores the received RAM.
It has a function to analyze the data on a and create serial data for lighting the LED head, and the clock creation unit 5a in this part receives the base clock from CPtJl and generates the LED head data (LED HEAD in the figure). D.A.
A clock signal (CLK in the figure) that is synchronized with the clock signal (TA) is generated and manually inputted to the LED print head main body 52. 7 is L
ED head lighting range setting circuit, programmable interval timer circuit (hereinafter referred to as timer circuit) 8
and three AND circuits that repeat a positive logic product between the output of the timer circuit 8 and the input of the LED head data from the LED head data creation section 5.

Input clock C of this LED head lighting range setting circuit 7
LKO-CLK2 is supplied from CPU 1. Further, a time table that determines the time width between the output O and the specific output of the timer circuit 8 is determined in advance according to the state of the printing paper, and is stored in the ROM 2 as the printing range setting time table 2a. Output 0 is used to regulate the printing range at the left end of the printing surface of the printing paper, and output 1 is used to regulate the printing range at the right end. Output 2 is a timer that regulates printing when the near end of the printing paper is detected, that is, it regulates printing in the column direction, and is used for the operation of setting the lighting range of the LED head in the row direction of the present invention. are not directly related.

As described above, when the printing paper state input section 6 detects a signal representing, for example, A4 size printing paper from the mechanism section 11, this state is stored in the RAM 3. On the other hand, when B4 size print data, which has a wider print range in the row direction than A4 size, is received from the host device, the LED data creation section 5 converts the rad data to the LEDs into B4 size data, and the LED head lighting range setting circuit 7 Enter.

However, since the A4 size was detected first, the CPU
I reads the print range setting time table 2a in the ROM 2 to set the print range for A4 size, and supplies the result to the timer circuit 8. The timer circuit 8 counts and outputs this time. This output and the above-mentioned LED head data are then logically ANDed in an AND circuit, and the LED head data matching the preselected printing paper is input to the LED head 52.

FIG. 2 is a time chart for setting the LED head lighting range. In this time chart, the clock (CLK
) and LED head data (LEDHEAD DATA
) is synchronized with the time chart shown in the figure, and is generated from the rad data creation unit 5 to the LED shown in FIG. Rad data is imported. Timer output O (position marked ■ in Figure 1), which regulates the left edge of the printing paper by lighting the LED head, and timer output 1 (position marked ■ in Figure 1), which also regulates the right edge, are output as shown in the figure. .

This output is finally output by the AND circuit of the 703 LED hand lighting range setting circuits shown in FIG.
Data in the range of the mesh portion of the time chart is input as an input signal to the ED head.

In this way, the lighting range of the LED head emits light only in the range that matches the printing range of the printing paper.

In this embodiment, the left and right print data are truncated from the actually received data, but if the left end is set as the first print start position that matches the size of the print paper, the beginning of the line can be There is no interruption, and it is possible to freely set the lighting range, including the presence or absence of this function, by using the initial settings of the dip switch, etc.

<Effects of the Invention> As explained above, according to the present invention, when the printing paper is small and the printing range is insufficient for the line direction printing data received from the host device, the LED is set according to the printing range of the printing paper. Since the head is lit, there is no needless lighting, and therefore toner is not wasted, so LED
This has the effect of prolonging the life of the print head and keeping toner consumption low.

[Brief explanation of the drawing]

FIG. 1 is a pull diagram of the LED head lighting range setting control of an electrophotographic printer which is an embodiment of the present invention. FIG. 2 is a time chart of the LED head lighting range setting control. A schematic configuration diagram of an electrophotographic printer according to an embodiment; FIG. 4 is a schematic side view of a size detecting means for printing paper on cut sheets; FIG. schematic side view,
FIG. 6 is an explanatory diagram showing the relationship between the LED head main body and the photosensitive drum in a conventional electrophotographic printer. 1-------- CPU, 2------- ROM,
2 a ------1 printing range setting table, 3--
...-RAM, 5--, LED head data creation section, 5a--clock creation section, 6 printing paper status input section, 7---LED head lighting range setting circuit,
8---1--Programmable interval timer circuit, 52---LED head body, 56--
---Single sheet, 64-・～----Continuous folding paper,
71---Continuously folded paper size detection means, 72
-・Slip paper size detection means, A N D-・, -A
ND circuit. 3rd figure name q ′1 Tsuji B Yote 5 figure

Claims (1)

[Scope of Claims] An electrophotographic printer capable of handling either a plurality of single sheets or continuous folded sheets, and provided with means for detecting the size of the printing sheets, comprising: printing. When printing data on any of the above printing papers,
The printing range of the printing paper is set by the means for detecting the size of the printing paper, and when the print data in the line direction exceeds the printing range, the printing range is limited to the set printing range by means consisting of a programmable interval timer circuit. An electrophotographic printer characterized in that an LED head lighting range control method is used, in which the LED head is turned on in a range exceeding the set printing range.