JP2022071702A - Image forming apparatus - Google Patents

Abstract

To solve the problem in which when a setting is performed to detect medium characteristics with a medium sensor, it is difficult to cover all market paper, and thus a product with print quality suitable for paper used by a user may not be obtained.SOLUTION: A user's selection from a product obtained by executing a test mode changes a threshold for medium discrimination.SELECTED DRAWING: Figure 6

Description

The present invention relates to an image forming apparatus such as an electrophotographic method and an electrostatic recording method.

Media characteristics such as paper thickness and surface properties are controlled in an image forming device that develops an electrostatic latent image formed on a photoconductor by laser beam light with toner, transfers the toner image to paper, and heat-fixes it. It is important as a parameter.

By using this control parameter, it is possible to realize the optimum fixing temperature and transport speed for paper. It is generally known that the characteristic information of the paper is set by the user operation from the operation unit provided in the image forming apparatus or on the driver screen. However, in recent years, a device in which a sensor for detecting media is provided inside an image forming device has appeared, and a mode for forming an image according to a detection result by a sensor for detecting media (hereinafter referred to as a media sensor) and manual operation. It has been proposed to include a mode for forming an image according to the input media characteristics (see, for example, Patent Document 1).

JP-A-2017-138406

However, since papers with various characteristics are used in the market and it is difficult to optimally detect media for all market papers, a mode for forming an image according to the detection result by the media sensor is used. There is a problem that the user may not be able to obtain a product with optimum print quality.

An object of the present invention is to provide an image forming apparatus capable of obtaining a product of appropriate print quality in a media sensor use mode.

In order to achieve the above object, the image forming apparatus of the present invention has an image forming means for forming an image on a recording material based on a predetermined image forming condition, and the recording material to the image forming means via a transport path. A transport means for transport, a media determination means provided in the transport path for determining the media characteristics of the recording material to be transported to the image forming means, and a change instruction means capable of changing the determination criteria of the media determination means. The media determination means has an automatic determination mode for forming an image according to the media characteristics determined by using the media determination means, and when an image is formed on a recording material in the automatic determination mode. When the media characteristic determined in 1 is used as the first media characteristic, the determination criterion of the media determination means is changed by the change instruction means so that the second media characteristic different from the first media characteristic can be determined. It is characterized by.

According to the present invention, it is possible to obtain a product of appropriate print quality in the media sensor use mode.

Sectional view of image forming apparatus Block Diagram Cross section of fuser Explanatory drawing of the configuration of the media sensor Explanatory diagram of media and image formation conditions Control flow chart Explanatory drawing of user notification screen

[Embodiment 1]
FIG. 1 is a cross-sectional view of an image forming apparatus 100 showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention. A basic configuration will be described with reference to FIGS. 1 and 2.

The control unit of FIG. 2 is composed of a CPU 10, a ROM 11, and a RAM 12. An instruction to start a print operation is input to the CPU 10 from an instruction / display means 13 such as an operation unit. According to the operation start instruction, the CPU 10 can drive and control a paper feed transport motor (not shown) to feed and transport paper.

Further, the CPU 10 can control the image forming unit 17. The image forming unit 17 includes high pressure, drive control, and laser scanners 122a to 122d of the cartridges 120a, 120b, 120c, 120d of FIG. 1, the intermediate transfer belt 130, the primary transfer units 123a to 123d, the secondary transfer unit 140, and the like. Can be controlled. Further, the CPU 10 can detect the opening / closing of the paper cassette by controlling the fixing device 170 for fixing the image formed by the image forming unit 17 and monitoring the paper cassette opening / closing sensor 180. ..

The ROM 11 stores an image forming procedure and a flowchart procedure used in the description below. The media sensor 14 can detect media characteristics such as surface properties and thickness of the conveyed paper. Details will be described later.

Next, a basic image forming operation will be described with reference to FIGS. 1 and 2. When the instruction / display means 13 or the like gives an instruction to start the printing operation, the CPU 10 starts the paper feeding operation from the paper feeding cassette 220. A paper feed transfer motor (not shown), which is a drive source of the paper feed pickup roller 151, is driven to rotate the paper feed pickup roller 151, and the paper in the paper feed cassette 220 is fed and conveyed one by one.

Next, the media characteristics of the picked up paper are detected by the media sensor 14. Then, the information read here is reflected in the image formation speed and the target temperature of the fuser 170.

Regarding the image formation speed, for example, image formation is performed at 1/1 speed for plain paper and thin paper, and image formation is performed at 1/2 speed for thick paper. Image formation is performed at a speed predetermined by the material. And transport. Further, the target temperature of the fuser 170 is determined according to the media characteristics, and the target temperature is lower in the case of thin paper and higher in the case of thick paper than plain paper.

The CPU 10 starts an image forming operation by the cartridges 120a, 120b, 120c, and 120d in time for the paper to arrive at the secondary transfer unit 140. 120a is yellow (hereinafter sometimes referred to as Y), 120b is magenta (hereinafter sometimes referred to as M), 120c is cyan (hereinafter sometimes referred to as C), and 120d is black (hereinafter sometimes referred to as K). ) Is a cartridge for forming an image. The configuration is such that the user can install and remove the cartridge.

After the surface of the photoconductor is charged by the charging roller, a latent image is formed on the photoconductor by the laser emitted from the laser scanner 122a. Then, the formed latent image is developed on the photoconductor by the toner in the developing apparatus. After that, the developed toner image is transferred to the intermediate transfer belt 130 of FIG. 1 by applying a primary transfer voltage to the primary transfer units 123a to 123d of FIG. The toner image transferred to the intermediate transfer belt 130 reaches the secondary transfer unit 140 by the rotation of the intermediate transfer belt 130.

The CPU 10 detects the position of the paper conveyed by the transfer roller 155 by monitoring the pre-registration transfer sensor 160. Then, in consideration of the timing when the paper tip reaches the pre-registration transfer sensor 160, the paper transfer is controlled so that the paper tip and the tip of the toner image on the intermediate transfer belt 130 coincide with each other at the secondary transfer unit 140. do. For example, when the paper arrives early with respect to the toner image, the paper is stopped by the pre-registration transfer roller 161 for a predetermined time, and then the transfer is restarted.

By applying the secondary transfer voltage to the paper and toner image that has reached the secondary transfer unit 140 as described above, the toner image is transferred to the paper. The paper after the secondary transfer is conveyed to the fuser 170. The details of the fuser 170 will be described later.

The CPU 10 heats and fixes the toner image on the paper to the paper by the fixing device 170, and then further conveys the paper to the downstream portion of the apparatus. When the tip of the paper after fixing reaches the paper transport sensor 171, the CPU 10 determines whether to transport the paper to the paper transport path 230 or the paper transport path 231 according to an instruction designated in advance from the instruction / display means 13. .. According to the judgment, the paper transfer destination is switched by switching the transfer flapper 172. Specifically, when the instruction from the instruction / display means 13 is a double-sided printing instruction, the paper is conveyed to the paper transport path 230 when front side printing is being performed, and when single-sided printing or double-sided printing is being printed on the back side. , Transport to the paper transport path 231.

When the paper is transported to the paper transport path 231, the transported paper is further downstream transported by the transport roller 232 and discharged to the output tray 196.

On the other hand, when the paper is transported to the paper transport path 230, the paper is transported by the reversing transport roller 162 located in the downstream portion and is drawn into the reversing portion A. After the paper is drawn into the reversing unit A, the transfer flapper 173 is switched, and the reversing transfer roller 162 is rotated in the reverse direction to switch back the paper and transfer the paper toward the secondary transfer unit 140. Then, the position of the paper is detected by monitoring the pre-registration transfer sensor 160 again by the CPU 10, and the paper is aligned with the tip of the toner image on the intermediate transfer belt 130 at the secondary transfer section 140. Control the transport of. After the toner image is transferred to the paper, it passes through the fuser 170, switches the transport flapper 172, transports the paper to the paper transport path 231, and discharges the paper to the paper output tray 196. This realizes double-sided printing.

When the paper is switched back by the reversing portion A, the paper length in the transport direction needs to be shorter than the length L of the reversing portion A.

Further, the CPU 10 can detect the opening / closing of the paper cassette 220 by monitoring the paper cassette opening / closing sensor 180. This makes it possible to control the paper feed cassette 220 so that the paper feed operation is not started when the paper cassette 220 is open.

The above basic image forming operation is an example, and the present invention is not limited to the above configuration.

<Explanation of fuser 170>
The configuration of fixing will be described with reference to FIG. The fuser 170 is an assembly including a heater holder 207, a fixing heater 204 fixedly arranged on the lower surface of the heater holder 207 along the length of the heater holder (in the direction perpendicular to the drawing), and an elastic layer fixing film 203.

Reference numeral 205 denotes a pressure roller, and both ends of the core metal are arranged so as to be rotatably bearing between the side plates of the fixing device. The fuser 170 is arranged in parallel with the pressurizing roller 205 with the fixing heater 204 side in contact with the pressurizing roller 205, and the both end sides of the heater holder 207 are pressed by a predetermined pressing force by an urging means (not shown). It is set to.

As a result, the surface of the fixing heater 204 is pressed against the elasticity of the pressure roller 205 with the fixing film 203 sandwiched therein to form a fixing nip portion 206 having a predetermined width. The pressure roller 205 is rotationally driven at a predetermined peripheral speed in the counterclockwise direction of the arrow by a drive mechanism (not shown). The fixing heater 204 has a resistance heating element formed on a ceramic substrate. The temperature detecting means 208 is in contact with the fixing heater 204. The CPU 10 detects the temperature of the fixing heater 204 and controls the power supply to the fixing heater 204 so that the temperature of the fixing heater 204 becomes a desired temperature.

The target temperature of the fixing heater 204 is determined by the type of paper to be passed through, the environmental temperature, and the like. The CPU 10 determines the target temperature of the fixing heater 204 according to the paper type set from the instruction / display means 13 or the paper type detected by the media sensor 14. As described above, the target temperature of the fuser 170 is determined according to the media characteristics, and the target temperature is lower in the case of thin paper and higher in the case of thick paper than plain paper.

<Explanation of the configuration of the media sensor 14 and the media settings>
Next, an example of the media sensor 14 will be described with reference to FIG. Inside the media sensor 14, an LED 481 is arranged as a light emitting element and a photodiode 480 is arranged as a light receiving element. The amount of reflected light emitted by the LED 481 can be detected by the photodiode 480. Further, a guide portion 483 into which the paper S rushes is provided.

The CPU 10 receives the input signal of the photodiode 480 as the output value of the media sensor 14. Then, it is possible to determine the type of paper (material / thickness of paper S) that is being passed according to the difference in the received value for each paper. Then, the CPU 10 optimally controls the image forming speed and the temperature of the fuser 170 according to the paper type detected here.

By using the media sensor 14 to determine the paper type in this way, it is not necessary for the user to bother to be aware of and set the paper type. Therefore, in the image forming apparatus 100 of the present embodiment, the setting using the media automatic detection mode in which the paper type is determined by the media sensor 14 is the default setting value (hereinafter, referred to as the media automatic detection mode). However, depending on the paper used by the user, the media sensor 14 may not be able to detect the optimum paper type, resulting in a non-optimal printed matter product. In preparation for such a case, a mode called a media user instruction mode, in which the user manually sets the paper type to be used, is also provided (hereinafter referred to as a media user instruction mode).

The configuration and media settings of the media sensor 14 used in the present invention have been described above. The configuration of the media sensor 14 described above is an example, and the present invention is not limited to this configuration. For example, a method of combining an ultrasonic sensor such as a piezoelectric element in addition to the light emitting element and the light receiving element described in the present invention is also effective. The present invention is an effective configuration even for the media sensor 14 having these other configurations.

<Explanation of changing the paper type discrimination threshold>
In recent years, there are a wide variety of papers distributed in the market and actually used by users (hereinafter referred to as market papers), and the media sensor 14 can determine the optimum paper type according to the characteristics of all market papers. It can be difficult.

Hereinafter, the relationship between the determination of the paper type by the media sensor 14 and the market paper will be described with reference to FIG. 5A. In FIG. 5A, a discrimination threshold value 1 (503) is set between the plain paper 1 reference paper (501) and the thin paper (505) so that the plain paper 1 reference paper (501) can be discriminated from the plain paper 1 (506) by the media sensor 14. It schematically shows that the discrimination threshold value 2 (504) is set between the 507) and the discriminant threshold value 2 (504). Therefore, if the discrimination result by the media sensor 14 is between the discrimination threshold value 1 (503) and the discrimination threshold value 2 (504), it can be determined that the paper is plain paper 1 (506). Further, in FIG. 5A, it is shown that the market paper (502) has a discrimination result extremely close to the discrimination threshold value 1 (503), and this market paper (502) forms an image as plain paper 1 (506). However, the paper has characteristics that are very close to those of thin paper.

Regarding the above-mentioned market paper 502, whether it is better to form an image with plain paper 1 or to form an image with thin paper depends on the media characteristics of the market paper 502. In addition, it may differ depending on the user's preference and product usage environment (temperature, humidity).

Generally, in the fuser 170 that heats and fixes the toner image on the paper, the toner melts better and the toner image adheres better when the fixing temperature is raised, but a phenomenon called heat curl occurs in which the paper bends due to heating. It will be easier.

For example, there is a case where a certain user does not attach importance to the sticking state of the toner image because there is no act such as rubbing the toner surface of the deliverable, but emphasizes that the curl of the deliverable is small because the matching is performed. Then, it is better for this user to discriminate the market paper 502 as thin paper.

Specifically, when this user uses the market paper 502, the discrimination threshold value 1 (503) between the thin paper and the plain paper 1 is changed so that the market paper 502 becomes the thin paper as shown in FIG. 5 (b). As described above, it can be realized by setting the discrimination threshold value 1'(508).

<Explanation of the flowchart for changing the paper type discrimination threshold>
FIG. 6 is a flowchart illustrating an operation outline of the image forming apparatus according to the present embodiment. This procedure is stored in the ROM 11 as a program and executed by the CPU 10.

The CPU 10 checks whether or not the print job has been accepted (step S601). When the print job has been received, it is next determined by the instruction / display means 13 whether or not the user has specified the media automatic detection mode (step S602). In the media automatic detection mode, paper transfer is started at a specified speed, media is detected by the media sensor (step S603), and the material is determined based on the media detection result (step S604). When the media automatic detection mode is not set in step S602, that is, when the media user instruction mode is set, the material used in the main printing is determined to be the material specified by the instruction / display means 13 (step S605). Then, image formation is performed according to the determined material setting (step S606). After that, it is determined whether it is the final page (step S607), and if it is the final page, this flowchart is terminated. If it is not the final page, the process returns to step S602, and paper transfer and image formation are performed.

If the print job has not been received in step S601, it is determined whether or not the test mode for changing the setting of the media automatic detection mode has been executed (step S608). The test mode can be executed by the user from the screen as shown in FIG. 7A on the instruction / display means 13. If the test mode has not been executed, the process returns to step S601. When the test mode is executed, paper transfer is started at a specified speed, media is detected by the media sensor (step S609), the material is determined based on the media detection result (step S610), and image formation is performed according to the material settings. (Step S611).

Next, based on the received value at the time of detection in step S609, the material closest to the material different from the material determined in step S610 is selected and determined as the material to be used in the main printing (step S612). .. If the media detection in step S609 is the market paper 502 of FIG. 5A, the plain paper 1 and the adjacent materials (thin paper and plain paper 2) are compared, and the material having a closer reception value is set as the proximity material. In the present embodiment, the market paper 502 to the thin paper 505 (503 of the discrimination threshold value 1) is closer than the plain paper 2507 (504 of the discrimination threshold value 2), so that the proximity material is the thin paper, so the thin paper is determined in step S612. become. Subsequently, paper transfer is started at a speed corresponding to the material determined in step S612, and image formation is performed according to the material setting (step S613).

At this point, a total of two deliverables image-formed with two different material settings are output, and a screen as shown in FIG. 7B is displayed on the instruction / display means 13 (step S614). If the cancel button is pressed here, the paper used by the user in this test mode wants to work with the result of the current media detection, so it ends without changing any settings. do. On the other hand, if the change button is pressed here, it means that the user wants to change the operation based on the current media detection result when the paper is used, so there are two media detection results in the media automatic detection mode. The media discrimination threshold is changed so as to be the material setting of the eyes (step S615). Specifically, the discrimination threshold is changed from 503 to 508 as shown in FIG. 5 (b).

As described above, since the media detection result of the media automatic detection mode is changed by the user selection from the deliverables that image is formed under the two different image formation conditions by executing the test mode, the subsequent media automatic Printing in the detection mode will output the product of print quality intended by the user.

[Explanation of Other Embodiments]
Although not particularly limited in the above, it is considered effective to limit the effect of the change of the present invention to the user because the user selects the product by looking at the deliverable.

It is also effective not to reflect in media discrimination even if the temperature and humidity that affect image formation are significantly different, and not to reflect in media discrimination depending on the job type content (paper feed stage, single-sided / double-sided, color / monochrome, etc.). I think there is.

As described above, by not reflecting the situation different from the situation in which the test mode is executed, it is possible to output the product of the print quality intended by the user for printing in the media automatic detection mode.

10 CPU
11 ROM
12 RAM
13 Instruction / display means 14 Media sensor 17 Image forming unit 170 Fuser

Claims (7)

An image forming means for forming an image on a recording material based on predetermined image forming conditions, and an image forming means.
A transport means for transporting the recording material to the image forming means via a transport path, and a transport means.
A media determining means provided in the transport path and determining the media characteristics of the recording material to be transported to the image forming means.
A change instruction means capable of changing the determination criteria of the media determination means is provided.
It has an automatic determination mode in which an image is formed according to the media characteristics determined by using the media determination means.
When the media characteristic determined by the media determination means is used as the first media characteristic when an image is formed on a recording material in the automatic determination mode, it can be determined as a second media characteristic different from the first media characteristic. In addition, an image forming apparatus characterized in that the determination criteria of the media determination means are changed by the change instruction means. In the image forming apparatus according to claim 1,
When an image is formed on a recording material in the automatic determination mode, an image is formed with the first media characteristic determined by the media determination means, and then the recording material is formed with the second media characteristic different from the first media characteristic. The change instruction means selects whether the image is formed and the recording material is determined to be the first media characteristic or the second media characteristic when the image is formed in the automatic determination mode. An image forming apparatus characterized by changing the determination criteria of the media determination means. In the image forming apparatus according to claim 1 or 2.
The method for selecting the second media characteristic is characterized in that the recording material has another media characteristic closest to the media characteristic determined by the media determination means when forming an image in the automatic determination mode. Image forming device. The image forming apparatus according to any one of claims 1 to 3.
The image forming apparatus is characterized in that the determination criteria of the media determination means are changed so that the media characteristics determined by the media determination means are changed to be determined to be the second media characteristics. The image forming apparatus according to any one of claims 1 to 4.
An image forming apparatus characterized in that the change of the media determination means is reflected when the user changes the determination criterion of the media determination means by the change instruction means, and is not reflected in the media determination of a user different from the time when the change is executed. .. The image forming apparatus according to any one of claims 1 to 5.
The change of the media judgment means is reflected at the time of the environmental temperature classification or the environmental humidity classification when the judgment standard of the media judgment means is changed by the change instruction means, and the change is reflected at the time of the environmental temperature classification or the environmental humidity classification different from the time of execution of the change. An image forming apparatus characterized in that it is not reflected in the media determination of. The image forming apparatus according to any one of claims 1 to 6.
At least one of paper feed stage, single-sided printing / double-sided printing, or color printing / monochrome printing can be set as the job type content.
The feature is that the change of the media determination means is reflected when the determination criterion of the media determination means is changed by the change instruction means, and is not reflected in the media determination when the job type content is different from that at the time of executing the change. Image forming device.

Images