Image formation apparatus, an image formation method, an image formation program, and a computer-readable recording medium

An image formation apparatus, an image formation method, an image formation program, and a computer-readable recording medium are provided, a rotation of the developer supply roller is controlled in order to prevent plugging of the developer supply roller based on quality information and environmental information.

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates to an image formation apparatus, an image formation method, an image formation program, and a computer-readable recording medium.

2. Description of the Related Art

A conventional method of preventing plugging by toner, a component of developer that is supplied from a toner holder to a development unit of an image formation apparatus, of a toner supply roller is proposed. For example, the method gives vibration to the toner supply roller at predetermined intervals by a vibrating unit that is arranged adjacent to a shaft that supports the toner supply roller or an outside surface of the toner supply roller (for example, Patent Reference 1).

However, the conventional method has the problem that the vibrator unit is required to include an expensive component such as a piezo-electric vibrator (such as crystal), a porcelain vibrator (such as one using barium titanate), or a magnetostrictive vibrator (such as a ferrite). Further, in order to protect the expensive vibrator, the configuration tends to be complicated, adding further costs.

SUMMARY

In an aspect of this disclosure, there are provided an image formation apparatus, an image formation method, an image formation program, and a computer-readable recording medium, whereby toner plugging, apparatus breakdown, and apparatus damage are prevented without a special mechanical configuration.

In an exemplary embodiment (FIG. 2A), there is provided an image formation apparatus, wherein a developer (toner) supply roller supplies a developer (toner) to a development unit, the image formation apparatus including,

a quality information acquiring unit (for example,201ainFIG. 2A) for acquiring a quality information set chosen by a user out of two or more predefined quality information sets about the quality of image formation,

an environmental information acquiring unit (for example,201binFIG. 2A) for acquiring an environmental information set about the present operational environment out of two or more predetermined environmental information sets about the operational environment of image formation, and

a controlling unit (for example,201cinFIG. 2A) for controlling rotation of the developer (toner) supply roller (for example,201dinFIG. 2A) in order to prevent plugging of the developer supply roller when forming an image based on the acquired quality information and the acquired environmental information.

According to another embodiment, the image formation apparatus includes

a storage unit for storing a table wherein information about contents of the control to be performed by the controlling unit is associated with the quality information and the environmental information, wherein

the controlling unit controls the rotational speed, the direction of the rotation, and the rotation time of the developer supply roller based on the table stored in the storage unit.

According to another embodiment, the image formation apparatus controls the developer supply roller with a combination of control before the image formation, control performed during the image formation, and control after the image formation based on the table stored in the storage unit.

According to another embodiment, the controlling unit measures an interval during which the image formation apparatus has been in a non-operating state (for example, with the power source turned off, or in an energy-saving mode), and rotates the developer supply roller at a predetermined speed for a predetermined time before the image formation, if the measured interval is greater than a predetermined interval.

In the aforementioned embodiment, an image formation method may be provided, wherein a developer supply roller supplies a developer to a development unit, the image formation method including,

a quality information acquisition step of acquiring a quality information set chosen by a user out of two or more predefined quality information sets about the quality of image formation,

an environmental information acquisition step of acquiring an environmental information set about the present operational environment out of two or more predetermined environmental information sets about the operational environment of image formation, and

a control step of controlling rotation of the developer supply roller in order to prevent plugging of the developer supply roller when forming an image based on the acquired quality information and the acquired environmental information.

According to another aspect of the embodiment of the present invention, the control step of the image formation method controls the rotational speed, the rotational direction, and the rotation time of the developer supply roller based on stored information, which stored information includes contents of control to be carried out at the control step which contents are associated with the acquired quality information and the environmental information.

According to another embodiment, the control step of the image formation method controls the rotational speed, the rotational direction, and the rotation time of the developer supply roller based on stored information, which stored information includes contents of control to be carried out at the control step which contents are associated with the acquired quality information and the environmental information.

According to another embodiment, the control step of the image formation method controls the developer supply roller by combining control performed before the image formation, control performed during the image formation, and control after the image formation based on the stored information.

According to another embodiment, the control step measures an interval during which the image formation apparatus is in the non-operating state, and rotates the developer supply roller for a predetermined time at a predetermined speed before the image formation, if the measured interval is greater than a predetermined interval.

In the aforementioned embodiment, an image formation program can be provided for a computer to perform the image formation method of the present invention.

In the aforementioned embodiment, a computer-readable recording medium can be provided that stores the image formation program of the present invention.

With the image formation apparatus, the image formation method, the image formation program, and the computer-readable recording medium according to the embodiment of the present invention, plugging of a toner supply roller can be prevented with a simple configuration wherein the rotation of the toner supply roller is controlled so that an apparatus breakdown and damage can be prevented.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the image formation apparatus, the image formation method, an image formation program, and the computer-readable recording medium of the present invention are described with reference to the accompanying drawings.

Embodiment

First, an image formation apparatus100according to the embodiment of the present invention is described with reference toFIG. 1, which is a cutaway view of the image formation apparatus100configured according to the embodiment of the present invention. The image formation apparatus100includes:

an exposure unit106;

a transfer belt108;

a feed roller111;

a paper feed tray112;

a recording medium (paper)113;

a secondary transfer roller114;

a fixing assembly115; and

a delivery roller116.

The image formation apparatus100is of a tandem type wherein the toner holders102B,102M,102C, and102Y containing toner of colors black (B), magenta (M), cyan (C), and yellow (Y), respectively, are arranged along the transfer belt108.

With reference toFIG. 1, the transfer belt108rotates counterclockwise, and the toner holders102B,102M,102C, and102Y are arranged in this sequence from the upstream side of rotation of the transfer belt108. The toner holders102B,102M,102C, and102Y are identical to each other, except that each toner holder contains toner of a uniquely assigned color as described above. Then, in the following, the toner holder102B and the toner supply roller101B are described as the representatives of the toner holders102and the toner supply rollers101, respectively.

When forming an image, the toner supply roller101B shown inFIG. 1is rotated clockwise (the clockwise rotational direction is called a “positive direction”, a rotation in the positive direction is called a “positive rotation”, a counterclockwise rotational direction is called a “negative direction”, and a rotation in the negative direction is called a “negative rotation”), and supplies black toner contained in the toner holder102B to the corresponding development unit103B. The rotational speed of the toner supply roller101B can be adjusted between 50 mm/sec and 160 mm/sec, where the rotational speed of 160 mm/sec is called a “full speed”.

The surface of the photo conductor104B is uniformly charged by the electrification unit105B. Then, the exposure unit106irradiates and exposes a laser light107B corresponding to the image of black onto the photo conductor104B that is uniformly charged by the electrification unit105B. In this way, an electrostatic latent image of the black image is formed on the photo conductor104B.

The development unit103B forms a toner image by applying the black toner to the electrostatic latent image, and the black toner image is formed on the photo conductor104B. The black toner image is transferred onto the transfer belt108by the primary transfer roller109B at a primary transfer position where the photo conductor104B and the transfer belt108make contact. In this way, the toner image formed with the black toner is placed on the transfer belt108. Then, the cleaner blade110B wipes away residual toner that remains on the surface of the photo conductor104B so that it is ready for the next image formation. Similarly, toner images in magenta, cyan, and yellow are formed on the transfer belt108so that all the toner images may be superposed.

The secondary transfer roller114transfers the superposed toner image to the paper113conveyed from the paper feed tray112with the feed roller111. Then, the fixing assembly115fixes the toner image to the paper113. Then, the paper113on which the toner image is fixed is discharged to the exterior of the image formation apparatus100by the delivery roller116.

Now, in image formation, low-speed printing is performed when, e.g., printing onto pasteboard, and printing at high density. If low-speed printing is continuously performed for a long time, since the flow of the toner in the vicinity of the toner supply rollers101becomes slow, there is a problem in that toner plugging of the toner supply rollers101is generated. If the operation is forced to continue with toner plugging occurring, the amount of the toner being supplied to the photoconductors104falls, and printing consistency becomes low. In the worst case, the toner supply rollers101may be damaged, and use of the image formation apparatus100may become impossible. Then, the image formation apparatus100according to the embodiment of the present invention prevents toner plugging by controlling the rotational speed, the rotational direction, and the rotation time of the toner supply rollers101before, during, and after image formation.

Next, the hardware configuration of the image formation apparatus100according to the embodiment of the present invention is described with reference to a block diagram inFIG. 2. As shown inFIG. 2, the image formation apparatus100includes a CPU201, a storage unit202, an LSI203for I/O control, a motor204, a clutch205, a drive transfer device206, and the toner supply rollers101B,101M,101C, and101Y, and a computer-readable recording medium207such as a CD-ROM for storing the image formation program.

The CPU201is for controlling processes of the image formation apparatus100. Further, the CPU201performs a toner plugging preventive operation before image formation, during image formation, and after image formation. The storage unit202stores information about the rotational speed, the rotational direction, and the rotation time of the toner supply rollers101for the toner plugging preventive operation.

Further, the CPU201controls the motor204and the clutch205by the LSI203for I/O control. The motor204is for rotating the toner supply rollers101through the drive transfer device206. Further, the clutch205is for stopping the rotation of the toner supply rollers101through the drive transfer device206. The rotational speed, the rotational direction, and the rotation time of the toner supply rollers101can be adjusted by the CPU201controlling the motor204through the LSI203for I/O control.

Next, the toner plugging preventive operation performed by the image formation apparatus100according to the embodiment of the present invention is described with reference to a table given inFIG. 3. First, a critical rotational speed S at which toner plugging may occur is described. The critical rotational speed S varies with the operational environment (such as temperature and humidity), quality and magnitude of the toner, the toner supply roller101, and the toner holder102. Here, about the configuration shown inFIG. 1, parameters Z are defined, namely, the diameter of toner (grain) is about 8 μm, the diameter of the toner supply rollers101is about 10 mm, and the smallest distance between the wall of each toner holder102and the corresponding toner supply roller101is about 0.75 mm. With the parameters Z, experiments conducted by the inventor hereto show that toner plugging can occur at a rotational speed of 60 mm/s or less. Accordingly, the critical rotational speed S is defined as 60 mm/s.

Further, the experiments show that the probability of toner plugging occurring depends on the time or the number of sheets processed when the toner supply rollers101are rotating below the critical rotational speed S. Specifically, if the operational environment is poor with the parameters Z, whenever one sheet is printed, toner plugging may occur; if the operational environment is normal, toner plugging may occur in 300 seconds or more; and if the operational environment is good, toner plugging does not occur.

Further, the experiments show how long the non-operating state of the toner supply rollers101may last before the toner plugging preventive operation should start. Specifically, with the parameters Z, toner plugging may occur if the non-operating state lasts 24 hours or more (non-operating state is such as a power source being turned off, or being in an energy-saving mode). Further, in the case that the non-operating state continues 24 hours or more, the experiments show that toner plugging can be fully prevented if the toner supply rollers101are rotated at the full speed in the positive direction for 2 seconds.

Next, the rotational speed of the toner supply rollers101, at which rotational speed toner plugging can be prevented, is described. The experiments show that toner plugging can be prevented if the rotational speed of the toner supply rollers101is 150 mm/s or greater with the parameters Z.

Further, the experiments show that, with the parameters Z, toner plugging of the toner supply rollers101can be prevented if the toner supply rollers101are rotated at the full speed (160 mm/s) for 2 to 10 seconds in either of the positive and the negative directions. Specifically, when the operational speed of the toner supply rollers101is less than the critical rotational speed S (60 mm/s), at which speed toner plugging may be generated, toner plugging can be prevented by rotating the toner supply rollers101

at the full speed for 10 seconds if during the operation,

at the full speed for 2 seconds if resuming operations from the non-operating state, and

at the full speed for 4 seconds in the positive direction and at the full speed for 2 seconds in the negative direction if entering the non-operating state.

Information about the contents (specific operations) of the toner plugging preventive operation that the image formation apparatus100performs is defined based on the experimental results, which information is stored in the storage unit202.FIG. 3is a table showing the contents of the toner plugging preventive operation that the image formation apparatus100according to the embodiment of the present invention performs. With reference toFIG. 3, the image formation apparatus100performs the toner plugging preventive operation based on the kind of printing request that is input by a user. Here, for example, three kinds are offered, namely, speed important, normal, and quality important. Further, the toner plugging preventive operation is based on the environmental conditions, which conditions are, for example, poor, normal, and good. Here, the CPU201determines the environmental condition based or operational environmental factors such as temperature and humidity.

For example, if the printing request that the user has input is “speed important”, and if the environmental condition is “poor”, the toner supply rollers101are rotated at the full speed in the positive direction for 10 seconds every 600 seconds during printing as shown inFIG. 3. Then, after printing, the toner supply rollers101are rotated at the full speed for 4 seconds in the positive direction, and at the full speed in the negative direction 2 seconds. If the printing request that the user has input is “normal”, and if the environmental condition is “normal”, the toner supply rollers101are rotated at the full speed in the positive direction for 10 seconds every 300 seconds during printing as shown inFIG. 3. Then, after printing, the toner supply rollers101are rotated at the full speed in the positive direction for 4 seconds, and then are rotated at the full speed in the negative direction for 2 seconds. Further, if the printing request that the user has input is “quality important”, and if the environmental condition is “good”, the toner supply rollers101are rotated at the full speed in the positive direction for 2 seconds before printing as shown inFIG. 3.

Next, with reference toFIG. 4, process steps of the toner plugging preventive operation carried out by the image formation apparatus100according to the embodiment of the present invention are described.FIG. 4is a flowchart that shows the process steps of the toner plugging preventive operation. As shown inFIG. 4, first, whether the CPU201receives a printing request is determined at step S401. The printing request is issued by the user operating a control panel (not illustrated). Here, three choices are available as for the printing request in this example as described above, namely, speed important, normal, and quality important.

At step S401, if no printing request is received (No at step S401), the process returns to step S401; and if the printing request is received (Yes at step S401), the process proceeds to step S402wherein the CPU201determines the environmental condition. Three environmental conditions are available for selection in this example as described above, namely, poor, normal, and good. The CPU201determines a choice based on operational environment factors such as temperature and humidity.

Then, at step S403, the CPU201determines whether the non-operating state has lasted for 24 hours or more. If the determination is negative (No at step S403), the process proceeds to step S405wherein the toner plugging preventive operation before printing is performed.

Otherwise, if the determination at step S403is affirmative (Yes at step S403), the CPU201causes the toner supply rollers101to rotate at the full speed in the positive direction for 2 seconds at step S404. Specifically, the CPU201rotates the motor204through the LSI203for I/O control, and rotates the toner supply rollers101at the full speed in the positive direction for 2 seconds through the drive transfer device206.

Then, at step S405, the CPU201performs the toner plugging preventive operation before printing. Specifically, if, for example, the printing request acquired at step S401is “quality important”, and if the environmental condition determined at step S402is “normal”, the information for the toner plugging preventive operation before printing corresponding to “quality important” and “normal” environment is read from the storage unit202(refer toFIG. 3), and the toner supply rollers101are rotated at the full speed in the positive direction for 2 seconds.

Then, at step S406, the CPU201starts printing. While printing, the CPU201performs the toner plugging preventive operation during printing at step S407. For example, if the printing request acquired in step S401is “quality important”, and the environmental condition determined at step S402is “normal”, the CPU201reads the information about the toner plugging preventive operation during printing corresponding to “quality important” and “normal” environment from the storage unit202(refer toFIG. 3), and rotates the toner supply rollers101at the full speed in the positive direction for 10 seconds every 300 seconds during printing.

Then, the CPU201ends printing at step S408. After printing, the CPU201performs the toner plugging preventive operation after printing at step S409, and the series of processes is ended. Specifically, for example, if the printing request acquired in step S401is “quality important” and the environmental condition determined in step S402is “normal”, the toner plugging preventive operation after printing is rotating the toner supply rollers101at the full speed in the positive direction for 4 seconds and rotating the toner supply rollers101at the full speed in the negative direction for 2 second as shown inFIG. 3.

As described above, according to the embodiments of the present invention, the image formation apparatus, the image formation method, the image formation program, and the computer-readable recording medium can be provided. According to them, plugging by toner can be prevented by only controlling the rotation of the toner supply roller so that the apparatus breakdown and damage can be prevented.

The embodiment of the image formation method as described above can be realized by a computer, such as a personal computer or a workstation, executing a program comprising the above process steps beforehand prepared. The program may be stored in a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, and a DVD, and is executed by the computer reading from the recording medium. Further, the program may be obtained through a transmission medium that can distribute the program through networks such as the Internet.

AVAILABILITY TO INDUSTRY

As described above, the image formation apparatus, the image formation method, the image formation program, and the computer-readable recording medium of the present invention are useful to in multifunction machines having, e.g., copying, facsimile, and printer functions; and are especially suitable for a copying machine that reads a manuscript and prints an output.

The present application is based on Japanese Priority Application No. 2006-032388 filed on Feb. 9, 2006 with the Japanese Patent Office, the entire contents of that are hereby incorporated by reference.