JPS6061274A - Driving method for led array light source - Google Patents

Abstract

PURPOSE:To enable to record with favorable continuity, by a method wherein the driving scanning direction for blocks in each LED element assembly segment in set to be opposite for each adjacent pair of segments, and the blocks of the same driving scanning order are simultaneously driven, in an electrophotographic-type printer. CONSTITUTION:In the LED element 14 assembly wherein one line consists of mX NXL bits, for example, common controlling signals C1-CN are sequentially impressed to blocks B11-B1N in a segments S1, and the controlling signals are impressed in the reverse order (starting from CN) on blocks B21-B2N in the adjacent segment S2. The other segments are similarly wired, and the blocks B11, B2N, B31, B4N... are simultaneously driven, and at the end blocks B1N, B21, B3N, B41... are simultaneously driven. Accordingly, while maintaining a rectilinear arrangement without requiring any structure modification such as staggering the LED elements and while maintaining high-speed property, the recording with favorable continuity can be performed without generating any large step between segment images.

Description

TECHNICAL FIELD The present invention relates to a method for driving an LED array light source for an optical writing head in a non-impact printer using an electrophotographic method.

Prior Art First, FIG. 1 shows an outline of a printer using an LED array as a light source. After the surface of a photoreceptor 1 is uniformly charged by a charger 2, the LED array and an imaging element (for example,
An electrostatic latent image is formed on the photoreceptor 1 by optical switching by 0N10FF of each LED element in the optical writing head 3 incorporating a SELFOC lens. Thereafter, the latent image is visualized by the developing unit 4 and transferred by the transfer charger 7 onto the transfer paper 6 fed by the paper feed roller 5. After the transfer, the transfer paper 6 is sent to a fixing unit 9 by a conveyance belt 8 and is fixed thereon, and is ejected by a paper ejection roller 10. On the other hand, the surface of the photoreceptor 1 is cleaned by a cleaning blade 11 in preparation for the next image formation.

Here, looking at the relationship between the LED array 12 and the photoreceptor 1 in the optical writing head 3, as shown in FIG.
The LED chips 13 of the array 12 are arranged in a line across the entire width in the main scanning direction (indicated by arrow M) (arrow S indicates the sub-scanning direction).

As shown in FIG.
), ・=D(Ll) ~ D(+, m) at the same time ○N1
One block B is a collection of m LED elements 14 controlled by 0FF, and B(11) to (IN)
, B (21) to B (2N).

As shown in ..., a collection of N blocks is divided into one segment S
One line is divided into L segments of 5(1) to S(L). Then, for each segment S, D
(11)-D(Lm), D(21)-D(2m),-,
Image signals D(LL) to D(Lm) are applied simultaneously, and each block B of each segment S is sequentially driven by common control signals C(1) to C(N). For example, first block B(11), B(21),...
, B (Ll) are simultaneously controlled by 0N10 FF, and then block B (12).

B (22), -, B (L2) are 0N10F at the same time
It is controlled by F. However, each block B (
11) to B(LN) as L I (
11) ~L I (LN) When looking at the state of the latent image in the - line, since the photoreceptor 1 is always moving at the linear velocity ■,
As shown in FIG. 4, a large step difference ΔQ occurs in the latent image between each segment, such as between L (IN) and L (21), and the image quality deteriorates. That is, if the time to write each segment S on the photoconductor 1 is T, and the time to write each segment S on the photoconductor 1 is t, then T=(N-1)t, and the step difference Δα becomes A Q=V-, T=V(N-1)t.

Purpose The present invention has been made in view of the above points, and includes segments 1 to yJ1. The object of the present invention is to obtain a method for driving an LED array light source that does not cause large steps between images of each segment while maintaining high speed using a dynamic method.

Structure One embodiment of the present invention will be described based on FIGS. 5 and 6. Also in this embodiment, 1 line = m x N x
The division method and arrangement method of the L-bit LED elements 14 are the same as those shown in FIG. 3, but the method of inputting the common control signals C(1) to C(N) to each block B is different. For example, blocks B (11) to B (
When common control signals C(1) to C(N) are sequentially applied to blocks B(21) to B(2N) of adjacent segment 5(2), the common control signals are reversely applied to blocks B(21) to B(2N) of adjacent segment 5(2). They are connected so that they are given in the order of C(N) to C(1). The same applies to the following segment S, and if it is an odd numbered segment, segment 5 (1)
If it is an even numbered segment, it is the same as segment 5(2). In other words, block B (11
) , B (2N) , B (31) , B (4
N), . . . are driven at the same time, and finally blocks B (IN), B (21)
, B (3N), B (41), . . . are driven simultaneously.

The state of the latent image formed in this way is shown in the sixth section.
In the figure, the arrows indicate the drive scanning direction of the block B in each segment S, and it can be seen that the direction is opposite for each adjacent segment S. As a result, L T (IN)・L 'f (21), L I between segments
(2N), L I (31), etc. are continuous, and no large steps occur. Also, N block division drive, L
High speed can be maintained by segment parallel drive.

It goes without saying that if the input of the common control signal is reversed, a latent image will be formed as shown in FIG.

Effects Since the present invention is configured as described above, the LED elements are arranged in a straight line without making any structural changes such as arranging them in a straight line, maintaining high speed, and eliminating large steps between each segment image. It is possible to perform recording with good continuity without causing any discontinuity.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of the printer, Fig. 2 is a front view showing the relationship between the optical writing head and the photoreceptor, Fig. 3 is a circuit diagram showing the conventional one-drive type, and Fig. 4 shows its drawbacks. 5 is a circuit diagram showing a -' embodiment of the present invention; FIG. 6 is a front view showing a latent image state; and FIG. 7 is a front view showing a modified example of a latent image state. be. 1... Photoconductor, 14... LED element, B... Block, S... Segment 1- Applicant Rico Co., Ltd. -

Claims (1)

[Claims] L is formed by dividing one line into L segments, with an aggregate of m-bit LED elements that are simultaneously controlled in 0N10FF as one block, and an aggregate of N blocks as one segment.
In an LED array light source in which all ED elements are linearly arranged, an LED array light source driving method is characterized in that each segment is simultaneously driven while the driving scanning direction of the blocks in each segment is reversed for each adjacent segment. .