JPS6243659A - Image forming device - Google Patents

Abstract

PURPOSE:To easily obtain an optimum image density level by forming images having plural density levels in test mode. CONSTITUTION:When an operator operates a test key 54, a CPU 44 detects the conveyance-directional length of recording paper on the basis of data from a size sensor 42 and computes data on the distance to density changeover points, e.g. A1-A7. The distance data is stored in the specific area of a RAM 48 and also set in a counter, and the data is used as movement data for a movable mirror 20. Then, the CPU 44 sets the voltage of an exposure light source 16 to the largest density level. Then when the CPU 44 sends a command to a motor driver 56, a mirror motor 64 is driven to move the mirror 20 in a specific direction. Then, the mirror 20 is moved by the distance corresponding to one density level set in the counter to detect the density level, and the quantity of exposure is varied to sections A1-A7 to perform development 34 and recording 38.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming apparatus, and in particular to an image forming apparatus that can select the density level of a recorded image from among a plurality of types, such as an electronic copying machine, a laser beam printer, The present invention relates to an image forming apparatus such as an LED printer.

(Prior Art) Conventional image forming apparatuses, such as electronic copying machines, are provided with means for setting the resulting image density. The fourth regulator sets the desired density level by that means.

(Problems to be Solved by the Invention) In conventional image forming apparatuses, it is not easy to set the image density optimally, and in order to obtain an image with the optimal density, images obtained in various modes and density levels are required. must be compared. This requires a large number of copies, which not only takes time and effort, but also wastes recording paper, developer, and the like.

Therefore, a main object of the present invention is to provide an image forming apparatus that can more easily set a desired density level.

(Means for Solving the Problems) Simply put, the present invention provides a means for specifying a test mode, and an image forming apparatus for forming images with at least two different density levels on one sheet of recording paper in the test mode. An image forming apparatus including a forming means.

(Function) When the test mode is set, images with at least two different density levels are formed on one sheet of recording paper by the image forming means.

(Effects of the Invention) According to the present invention, since images of different density levels can be simultaneously formed on one sheet of recording paper, comparison of density levels can be performed more easily than in the past. Therefore, the so-called
There are fewer "test prints" than in the past, making it easier to set density levels.

At the same time, waste of recording paper and developer can be minimized.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIG. 2 is a structural diagram showing the internal structure of an electronic copying machine as an embodiment of the present invention. The electronic copying machine 10 has a main body 1
2, and a document table 14 is provided on the upper surface of the main body 12. On this document table 14, in the embodiment, A D F
(Automatic Document Feed
er) is provided.

An exposure light source 16 is provided below the document table 14 inside the main body 12 so as to be movable in the direction of the arrow. This exposure light source 16
A reflective &11118 like a concave mirror and a movable mirror 20 that move integrally with the light source 16 are provided in conjunction with the light source 16.

Light from the exposure light source 16 is reflected by a reflecting mirror 18 and irradiated onto a document (not shown) placed on a document table 14, and the reflected light from there, that is, the document image is incident on a movable mirror 20. The original image incident on the movable mirror 20 is exposed to the exposure light source 1
6 are received by movable mirrors 22 and 24 which are movable in the direction of the arrow. The original images from these movable mirrors 24 are focused by a zoom lens 26, and
8, the image is projected and imaged onto the photoreceptor 30.

A charging corotron 32 is provided in conjunction with the photoreceptor 30 to uniformly charge the photoreceptor 30 prior to exposure to an original image. The photoreceptor drum 30 is rotatably provided in the direction of the arrow, and a developing device 34 is provided downstream of the exposure position of the photoreceptor 30 by the fixed mirror 28 for developing an electrostatic latent image formed by the exposure into a toner image. is provided.

Further downstream of the developing device 34, a transfer corotron 40 is provided for transferring the above-described toner image onto the recording paper 38 fed from the paper feed center 36. A recording paper 38 to which a toner image has been transferred by this transfer corotron 40
is fixed and discharged in a subsequent process as is well known.

A size sensor 42 is provided in association with the paper feed cassette 36 to detect the size of the recording paper 38 accommodated in the paper feed cassette 36 . This first sensor 42
For example, a photo sensor, a magnetic sensor or a microswitch can be used.

FIG. 3 is a block diagram showing an example of the control system of the embodiment shown in FIG. The control system includes a CPU 44, which includes a ROM 46 for pre-storing the control program and necessary information described above, and an RA having a timer area, a counter area, or other storage areas.
M48 is connected. The CPU 44 further includes an I10
A boat 50 is connected. This I10 boat 50 has
A key matrix 52 is connected, and this key matrix 5
2 is connected to a test key 54 provided on the operation panel for setting a test mode.

A size sensor 42 located at the location shown in FIG. 2 is also connected to this I10 boat 50. I10 boat 50
Further, a motor driver 56 and an AVR unit 58 are connected. The motor driver 56 is connected to the photoreceptor 30
a main motor 60 for rotating the , and an exposure light source 1
6, a driving voltage is applied to the mirror motor 62 for driving the movable member 1120. An encoder 66 is connected to the mirror motor 64, and a pulse signal from the encoder 66 is input to the I10 port 50.

The AVR unit 58 includes an exposure light source 16. The charging corotron 32 and the developing device 34 are connected, and therefore the AVR unit 58 applies a voltage to the exposure light source 16 to determine the amount of exposure light, and the charging corotron 32
A high voltage for controlling the charging voltage is applied to the developing device 34, and a developing bias is applied to the developing device 34.

FIG. 1 is an illustrative view showing an example of recording paper on which an image is formed according to this embodiment. In this embodiment, as shown in FIG. 1, the density level of the image recorded on one sheet of recording paper 38 is switched to a plurality of levels (seven levels in this embodiment) for copying.

Here, with reference to FIG. 4, the image forming operation as shown in FIG. 1 will be described. Prior to the first step S1, if the operator wishes to obtain a test image as shown in FIG. 1, he operates the test key 54 (FIG. 3). Then, in the first step S1, the CPU 44 detects the length of the recording paper in the conveyance direction at that time based on the size data from the size sensor 42, and moves it to each of the density switching points A1 to A7 shown in FIG. Calculate distance data. If seven density levels are to be recorded on one sheet of recording paper as shown in FIG.
4, in this step S1, distance data is obtained by dividing the length of the recording paper 38 in one general feeding direction into seven equal parts.

Then, in the next step S3, the CPU 44 stores the distance data obtained by the calculation in a predetermined area of the RAM 48, and sets it in a counter (not shown) formed in the RAM 48. The distance data thus obtained is used as movement J distance data of the movable mirror 20 (FIG. 2).

In the next step S5, the CPU 44 gives a command to the AVR unit 58 to set the voltage of the exposure light source 16 so as to obtain the highest density level. That is,
In step S5, the amount of exposure light from the exposure light source 16 is set to produce the darkest image.

In the next step S7, the CPU 44 controls the motor driver 5.
Give instructions to 6. In response, the mirror motor 64 is energized, and the exposure light source 16, that is, the movable mirror 20 starts moving in a predetermined direction. Then, when the CPU 44 detects that the image position has been reached in step S9 based on the pulses from the encoder 66, in the next step Sll, the CPU 44 decrements the counter in the RAM 48 for each pulse from the encoder 66. do. Then, in step S13, it is determined whether the counter has reached "0".

When it is detected in step S13 that the counter has become "0", that is, when it is detected that the movable mirror 2o has moved by the distance data for one density level set in the counter in the previous step S3, C.P.
In the next step 315, U44 determines whether control for all density levels has been completed.

If it has not finished yet, the CPU 44 sets the distance data previously stored in the RAM 48 in step S3 in the counter in the next step S17, and sets the distance data to the next density level in step S19. gives a command to the AVR unit 58. Therefore, in the second division until the counter reaches "0" in step S13, the exposure light amount by the exposure light source 16 is set so that the density level is one step lower than the first division.

In this way, repeat steps 5ll-319,
If "YES" is determined in step S15, that is, if the lightest density level is set in the seventh division, the process proceeds to the next process.

In this way, the amount of exposure light from the exposure light source 16 is changed for each of the sections A1 to A7 shown in FIG.
4 (FIG. 2), the density of the toner image developed on the recording paper 38, that is, the density of the image recorded on the recording paper 38, is divided into seven levels as shown in FIG. Therefore, the operator can set the required density level just by looking at a single test sheet as shown in FIG.

FIGS. 5 and 6 are illustrative views showing other examples of images formed on recording paper, respectively. In the example in Figure 5,
In the example shown in FIG. 1, the area of the recording paper 38 was divided only in the direction of transport, but the area of the recording paper 38 is divided not only in the direction of transport, but also in the direction perpendicular to that direction, so that it can be divided into more areas. Images are formed at different density levels.

The image shown in FIG. 5, like the image shown in FIG. 6, can be formed by, for example, an LED printer or a laser beam printer, in which the amount of exposure light can be varied in a direction perpendicular to the conveyance direction of the recording paper. I can do it.

In the example shown in FIG. 6, in an electronic copying machine having a printing function, a symbol indicating a mode is printed in each section (area) of the recording paper 38 divided into four parts. In other words, “N4
'' indicates the fourth stage density level, that is, the intermediate stage density level, "AE" indicates the density level in automatic exposure mode, and "P" indicates the density level in photo original mode. , and "C" indicates the density level in contrast enhancement mode.

By printing symbols in each area or section in this way, it is very convenient for the operator to be able to determine at a glance which mode to set.

Note that the symbols shown in FIG. 6 are merely examples, and it goes without saying that other arbitrary symbols can be added depending on the respective density levels.

FIG. 7 is a structural diagram showing the internal structure of a laser beam printer as another embodiment of the present invention. This laser beam printer 100 includes a main body 112, and a document table 114 is formed above the main body 112. Original table 11
4, an integral body consisting of an exposure light source 1162, a reflecting mirror 118, and a movable mirror 120 is provided so as to be movable in the direction of the arrow.

The original image incident on the movable mirror 120 is incident on the light receiving element 180 through the movable mirrors 122 and 124 and through the lens 126. The light receiving element 128 photoelectrically converts the incident original image and outputs an electric signal corresponding to the original. The electrical signal from the light receiving element 180 is given to the image processing section 182. In this image processing unit 182, the image is resolved into approximately 256 pixels (dots) per ml 112, and the density level of each pixel is divided into, for example, 12 levels and stored in a memory (not shown) together with the density levels. Ru. According to the data stored in the memory of the image processing unit 182, the laser scanner 184 outputs a laser beam for each pixel. This laser scanner 184
The laser beam from is reflected by the fixture 1128 and is incident on the photoreceptor 130.

Associated with photoreceptor 130 is a charging corotron 132 . as in the previous FIG. 2 embodiment. A developing device 134 and a transfer corotron 140 are provided.

Therefore, the toner image is transferred by the transfer corotron 140 onto the recording paper 138 fed from the paper feed trays 1 to 136.

The operation unit 186 shown in FIG. 8 has the eggplant 1 to keys 154 recessed therein, and is also provided with a display 188 and a portion designation key 190. The display 188 asks the operator which part of the original document is to be recorded by changing the density, and displays, for example, ``Test point correct''. Looking at the display on the display 188, the operator sets which part of each part shown in FIG. 9 should be test printed. For example, part A6
In order to set the
'' is operated, a portion A6 not shown in FIG. 9 is used for the test mode.

When the test key 154 is operated, the image processing section 182 corrects the density level of the image data in the shaded portion A6 in FIG. 9 and stores it in a predetermined area of the memory. In FIG. 10, among the stored original data, data corresponding to part A6 (for example, address 0
51000000~) and read the other parts A1~A5
Then, corrections of density levels of +6 to +5 are added and stored in memory areas A7 to A12. At this time, since the density level has 12 levels from "0 to OB", if it is below "O", it is stored as "O", and if it is above "OB", it is stored as "OB".

Thereafter, data is sequentially retrieved from the memory area corresponding to the recording paper 138, and the output of the laser beam from the laser scanner 184 is changed according to the data.

Then, as shown in FIG. 11, images with different density levels are recorded in 12 areas on the recording paper 138. It goes without saying that the images recorded at this time are of the same portion A6 (FIG. 9) in each portion.

Note that in the method shown in FIG. 10, the memory capacity in the image processing section 182 becomes very large, so when the test mode is set and the section designation key 190 is operated, the corresponding section (in the illustrated example, the section All you have to do is store only the data in 〇) in that memory. In this case, the memory area will only need to have a capacity that can store data for 1) 14 minutes.

In any of the embodiments described above, in order to change the density level of the recorded image, exposure means, the exposure light source 16 in the embodiment of FIG. 2 and the laser scanner 184 in the embodiment of FIG. Changed the amount of light.

However, in order to change the density of the recorded image 6, it is necessary to change the charging potential by the charging corotron 32 (or 132) and the developing bias in the developing device 34 (or 134), which are closely related to the density of the recorded image, that is, the toner image 6. Of course, it is also possible to do so. In this case, settings will be made in the AVR unit 58 shown in FIG. 3 to change the charging voltage and developing bias.

Furthermore, in the above-described embodiment, the setting of the density level in the case of monochrome was explained. However, the present invention can also be applied to color tone settings for color recording. When setting the color tone, similarly, the recording paper may be divided into a plurality of areas, and each area may be recorded with a different color tone.

[Brief explanation of drawings]

FIG. 1 is an illustrative view showing an example of recording paper on which an image is formed according to an embodiment of the present invention. FIG. 2 is a structural diagram showing the internal structure of an electronic copying machine as an embodiment of the present invention. FIG. 3 is a block diagram showing an example of the control system of the embodiment shown in FIG. FIG. 4 is a flow diagram for explaining the operation for obtaining a recorded image as shown in FIG. 1 according to this embodiment. FIGS. 5 and 6 are illustrative views showing other examples of recorded images, respectively. FIG. 7 is a structural diagram showing the internal structure of a laser beam printer as another embodiment of the present invention. FIG. 8 is an illustrative view showing the operating section of the embodiment shown in FIG. FIG. 9 is an illustrative diagram showing "parts" used in the test mode. FIG. 1O is an illustrative diagram showing a manner in which the density level is corrected in the image processing section of the embodiment shown in FIG. FIG. 11 is an illustrative view showing an example of a recorded image obtained by this embodiment. In the figure, 16, 116 is an exposure light source, 20° 120 is a movable mirror, 30, 130 is a photoreceptor, 32° 132 is a charging corotron, 34, 134 is a developing device, 42 is a size sensor, and 44 is a CP [J % 58 is AVR unit, 6
4 is a mirror motor, 66 is an encoder, 182 is an image processing section, and 184 is a laser scanner. Patent Applicant Sanyo Electric Co., Ltd. Agent Patent Attorney Yama 1) Yoshito (and 1 other person) Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. Means for specifying a test mode, and means for specifying at least two
An image forming apparatus comprising an image forming means for forming images with different density levels. 2. The image forming means includes a photoreceptor, a latent image forming means for forming an electrostatic latent image on the photoreceptor, a developing means for developing the electrostatic latent image into a toner image, and a toner image being developed by the developing means. 2. The image forming apparatus according to claim 1, further comprising density changing means for varying the density level of said toner image. 3. The image forming apparatus according to claim 2, wherein the density changing means includes means for dividing the photoreceptor into at least two regions. 4. The latent image forming means includes an exposure means, and the density changing means includes an exposure light amount changing means for changing the amount of exposure light by the exposing means for each of the divided areas. image forming device. 5. The image forming apparatus according to claim 3 or 4, wherein the density changing means includes bias changing means for changing the bias voltage in the developing means for each of the divided regions. 6. The latent image forming means includes a charging means for applying a charge on the photoreceptor, and the density changing means changes the charging voltage for changing the charging voltage by the charging means for each divided area. An image forming apparatus according to any one of claims 3 to 5, comprising means. 7. The latent image forming means includes a dot latent image forming means for forming a latent image of dots gathered on the photoreceptor, and the density changing means acts on the dot latent image forming means to change the divided latent image. 4. The image forming apparatus according to claim 3, further comprising density changing means for changing the aggregate density for each area.