JP2001335185A - Sheet thickness detecting device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set image forming control according to the detected thickness by detecting the thickness itself of paper with simple constitution. SOLUTION: This image forming device has a regist roller 215 to which carried paper is allowed to abut and a TOP sensor 315 for detecting the paper on the downstream side of the regist roller 215, and the regist roller 215 is constituted so that the abutting position becomes different according to the thickness of the paper, and is constituted so as to detect the thickness of the paper from a time difference (ta<tb) until the paper Sa and Sb are detected by the TOP sensor 315 after allowing the paper Sa and Sb to abut to the regist roller 215.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet thickness detecting device for detecting the thickness of a sheet, and a printer provided with the same.
The present invention relates to an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a printer or a copying machine, the type of sheet as a sheet is designated by an external device, the thickness of the sheet is determined based on the designation, and the process conditions for image formation are determined. Decided and controlled.

For example, the thickness of a sheet is specified through an external interface, and a target temperature for temperature control of a fixing unit is determined according to the specification (code).

[0004] The above-mentioned specification of the thickness of the sheet can also be specified by hardware such as switches (for example, an operation unit installed in the image forming apparatus).

[0005]

However, in the above-described conventional apparatus, it is necessary to first specify the thickness of the sheet, either from outside or from a switch. For example, in a network environment used by many users, it is complicated to make all users perform this operation.

If the thickness of the paper is divided into multiple stages,
For example, in the case of thin paper, the target temperature of the fixing temperature control can be set lower, which can contribute to energy saving. However, the conventional configuration is still complicated.

Therefore, a mechanism for automatically judging the thickness of the sheet is desired. However, a mechanism that requires space in the apparatus should not be desired for judging the thickness of the sheet.
It must be as simple as possible.

Accordingly, it is an object of the present invention to be able to detect the thickness of a sheet itself with a simple configuration and to set image forming control according to the detected thickness.

[0009]

In order to achieve the above object, a representative sheet thickness detecting apparatus according to the present invention comprises a contacting means for contacting a conveyed sheet and a downstream side of the contacting means. Detecting means for detecting a sheet at
The abutting means is configured so that the abutting position varies according to the thickness of the sheet, and the thickness of the sheet is determined based on a time difference between when the sheet abuts on the abutting means and when the sheet is detected by the detecting means. Characterized in that it is configured to detect the

Alternatively, there is provided a detecting means for detecting the conveyed sheet, and a phase detecting means for detecting a predetermined phase of the rotating means which is rotated by being pushed by the sheet passing through the detecting means, The rotating means is configured so that the contact position varies according to the thickness of the sheet, and the sheet thickness is determined from the time difference between when the detecting means detects the sheet and when the phase detecting means detects the rotating means. Characterized in that it is configured to detect the

According to the above configuration, the thickness of the sheet itself can be detected with a simple configuration.

An image forming apparatus for forming an image on a sheet is provided with the sheet thickness detecting device having the above-mentioned configuration, and the image forming control is variably set according to the sheet thickness detected by the sheet thickness detecting device. As a result, the thickness of the paper itself can be detected with a simple configuration without requiring any external or on-device setting, and
Image formation control can be set according to the detected thickness.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image forming apparatus provided with a sheet thickness detecting device to which the present invention is applied will be described in detail with reference to the drawings. In the following description,
A printer is illustrated as an example of the image forming apparatus.

First Embodiment A printer according to a first embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a block diagram of a printer system including a printer controller and a printer engine according to a first embodiment of the present invention. 101 is a display, 1
02 is a host computer. Reference numeral 103 denotes a printer controller which converts image data transmitted from the host computer 102 into an image signal so that raster scanning can be performed, and controls the printer engine 104 via an interface. The printer controller 103 and the printer engine 104 are both housed in the same printer housing.

The components in the printer controller 103 are as follows. 103a is a display unit on the surface of the printer housing, 103
b, an operation unit on the surface of the printer housing; 103c, a controller CPU; 103d, a ROM accessed by the CPU 103c;
3e is a RAM accessed by the CPU 103c.

FIG. 2 is a mechanical configuration diagram of the printer according to the first embodiment. The printer includes a main body 201 and an optional paper feeder 202 as an option.

Reference numeral 203 denotes a front cover. When the front cover is opened, an MPT (Multi-Purpose Tray) 204 serving as a manual feed tray is provided.
Can be used. Reference numeral 205 denotes a flag of a sensor on the MPT 204 that detects the presence of a sheet. Reference numeral 206 denotes an MPT paper feed roller for conveying the paper on the MPT 204 into the printer.

Reference numeral 207 denotes a standard paper feeding unit PCT (Paper Cass
ette Tray). Reference numeral 208 denotes a flag of a sensor on the PCT 207 for detecting the presence of a sheet. Reference numeral 209 denotes a PCT paper feed roller for conveying the paper on the PCT 207 to the inside of the printer.

Reference numeral 210 denotes an optional paper feeding unit OPT (Opti
onal Paper cassette Tray). 211 is a flag of a sensor on the OPT 210 that detects the presence of a sheet. 212 is O
OP for transporting the paper on PT210 into the printer
T-feed roller.

Reference numeral 213 denotes a transport roller for further transporting the paper fed from the PCT 207 and the OPT 210 to the inside of the printer.

The paper fed from any of the MPT 204, PCT 207, and OPT 210 is stored in the flag 21 of the pre-registration sensor.
It is detected that the leading end has reached the position 4, and after a predetermined time, the sheet feeding control ends. At this time, since the leading end of the sheet is in contact with the registration roller 215 that has not been driven at this time, a loop is formed, and the sheet is transported in a correct direction.
By driving the predetermined clutch, power is supplied to the registration roller 215.
The sheet is further conveyed to the rear by being transmitted to. Immediately after the registration roller 215, TOP which is a detection means
There is a sensor flag 216 called a sensor, which synchronizes the image of the sheet conveyed with the image.

Reference numeral 217 denotes a known process cartridge. A photosensitive drum 219 as an image carrier, a primary charging roller 218 and a developing cylinder 220 as process means acting thereon are provided inside. 221 is the photosensitive drum 219
Is a transfer roller for transferring the image formed on the sheet to the paper.

To write the electrostatic latent image on the photosensitive drum 219, a predetermined laser beam is rotated in a scanner unit 222 by a polygon mirror 224 driven by a motor 223.
To the photosensitive drum 219 by the return mirror 225.
By irradiation.

After the paper passes the toner transfer position, the paper is conveyed by conveyance belts 226a and 226b to a fixing device including a fixing roller 227 and a pressure roller 228, where the toner image is fixed on the paper.

Reference numeral 229 denotes a sheet discharge sensor flag which detects the presence of a sheet immediately after the fixing device.

The paper that has passed through the fixing device is further discharged by a paper discharge roller.
Conveyed by 230. Figure 2 shows the face-up tray 231
When the paper is opened as shown in (1), the paper is stacked on the face-up tray 231. Also, face-up tray 231
When is closed, the paper reaches the paper discharge roller 232 and is stacked on the face-down tray 233.

Reference numeral 234 denotes an upper door. When the upper door is opened upward, the process cartridge 217 can be taken in and out.

FIG. 3 is an electrical configuration diagram of the printer engine of the first embodiment.

Reference numeral 301 denotes an electric circuit unit of the printer engine. 302 is a microprocessor and 303 is its core. The microprocessor 302 includes a CPU 304, a ROM 305, and a RAM 306 inside a core 303, and GAs (Gate Arrays) 307a to 307d connected to the core 303.

Reference numeral 308 denotes an MPT paper presence sensor, and reference numeral 309 denotes an MPT.
Feed roller drive solenoid, 310 is PCT paper presence sensor, 311 is PCT feed roller drive solenoid, 312 is OP
A T sheet presence sensor, 313 is an OPT feed roller driving solenoid, 330 is a pre-registration sensor, and 331 is a registration roller driving solenoid.

Each roller rotates by driving each of the above-mentioned solenoids while the main motor 314 is rotating.

Reference numeral 315 denotes a TOP sensor serving as detecting means, and 316 denotes a paper discharge sensor. Reference numeral 317 denotes an interface between the optional sheet feeding device and a checker exclusively connected to the printer main body. This checker is used by a service technician for checking the status of the printer and performing a predetermined operation.

Reference numeral 318 denotes a switch for instructing a test print for outputting a test image for checking the operation of the printer. A switch 319 detects the open / closed state of the door 234 and turns off the high voltage circuit inside the printer when the door 234 is open. A jumper 320 indicates the type of power supply of the printer.

An external interface 321 allows the printer engine 104 to communicate with the printer controller 103. Reference numeral 322 denotes an electric circuit of the scanner unit 222, 323 denotes an electric circuit for controlling high voltage of charging, development and transfer, and 324 denotes an electric circuit of a fixing device. 325 is a fan for cooling the inside of the printer.

The printer engine 104 sends a command to the printer controller 103 via the external interface 321.
A BD signal is output on the BDO. This is a signal indicating that the polygon mirror 224 has a predetermined phase. When an image forming operation is performed on each sheet, horizontal scanning is performed when an image of one frame is received in a raster form through VDO and / VDO. Line synchronization signal. The first BD signal for each frame is called a TOP signal.

FIG. 4 is a diagram showing sheet registration in the printer of the first embodiment. FIG. 4 (a)
Sa is thin plain paper. After the registration roller 215, which is a registration unit, is driven and the time Ta has elapsed, the paper Sa
Is detected by a TOP sensor 315 which is a detecting means. FIG.
Sb in (b) is thick plain paper. Registration roller 21
After the driving of 5, when the time tb has elapsed, the sheet Sb is detected by the TOP sensor 315.

As shown in FIG. 4, since the position of the leading end of the sheet at the time of registration differs depending on the thickness of the sheet, the time from the start of driving of the registration roller 215 to the detection by the TOP sensor 315 is also ta <tb, Different.

FIG. 5 is a flowchart showing the procedure of sheet registration, sheet thickness detection, and fixing unit temperature adjustment setting in the printer of the first embodiment.

First, after the start of paper feeding, the pre-registration sensor 330
When the leading edge of the sheet is detected, the paper feed control is terminated after a predetermined time, thereby forming a sheet loop before the registration roller 215 (S501 to S502).

Next, the registration roller driving solenoid 331
, The conveyance of the sheet by the registration rollers 215 is started (S503), and at the same time, time counting from this point is started (S504).

If the top sensor 315 detects the arrival of the leading edge of the sheet (S505), the time required from the start of driving of the registration roller 215 is compared with a predetermined threshold (S506). Judgment is made as paper, and the temperature control of the fixing device suitable for the plain paper is performed (S507). If the temperature exceeds the threshold value, the paper is judged as thick paper (paper thicker than plain paper). Perform temperature control (S50
8). Since thick paper is thicker than plain paper, it absorbs more heat than plain paper. Therefore, the above-mentioned temperature control temperature (target temperature) of the fixing device is set higher.

As described above, according to the present embodiment, the thickness of the paper itself can be detected with a simple configuration, thereby eliminating the trouble of designating the thickness of the paper from outside. Further, fine control corresponding to the thickness of the sheet is possible. Therefore, the image forming operation according to the thickness of the sheet can be performed by the apparatus. Furthermore, since it has a simple configuration, there is little influence on the size and cost of the apparatus.

[Second Embodiment] Referring to FIGS. 6 and 7,
A printer according to a second embodiment of the present invention will be described in detail. FIG. 6 is a diagram illustrating the operation of the registration mechanism in the printer according to the second embodiment. The same reference numerals are used for configurations common to the first embodiment.

In the second embodiment, a registration plate 601 is provided in place of the registration roller 215 of the first embodiment, and the conveying direction is corrected by abutting the leading end of the sheet S on the registration plate 601. It has become.
Further, a transport roller pair 602 that can be brought into contact with and separated from the resist plate 601 is provided upstream of the resist plate 601. Hereinafter, FIGS.
(D) will be described step by step.

In FIG. 6 (a), the conveying roller pair 602 is spaced apart from the sheet S by a sufficient distance. Then, the resist plate 601 is driven so as to close the transport path downstream of the transport roller pair 602. Here, from the pre-registration sensor 330 to the registration plate 601, a loop (deflection) occurs on the paper during registration.
The transport path is configured so that is not formed.

In FIG. 6B, the sheet S is in a state in which the leading end is in contact with the registration plate 601 and the conveyance direction is corrected.
Are held between the pair of transport rollers 602.

In FIG. 6C, the registration plate 601 opens the transport path, and the sheet S is transported by the transport roller pair 602.

In FIG. 6D, the paper S is transported by the pair of transport rollers 60.
The sheet is conveyed by a pair of rollers downstream of 2, for example, a pair of the photosensitive drum 219 and the transfer roller 221, and the conveyance by the pair of conveyance rollers 602 becomes unnecessary, so the conveyance roller pair 602 is separated.

FIG. 7 is a diagram showing registration of a sheet in the printer according to the second embodiment. FIG. 7 (a)
Sa is thin plain paper. After the driving of the resist plate 601 serving as the resist means, the paper S
“a” is detected by a TOP sensor 315 which is a detecting means. Sb in FIG. 7B is thick plain paper. After the registration plate 601 has been driven and the time tb has elapsed, the sheet Sb
Detected by sensor 315.

As shown in FIG. 7, since the position of the leading end of the sheet at the time of registration differs depending on the thickness of the sheet, the time from the start of driving of the registration plate 601 to the detection by the TOP sensor 315 is also ta <tb, Different. By utilizing this, the thickness of the sheet is determined according to the first embodiment.

Further, according to the present embodiment, the closer the angle formed between the resist plate 601 and the transport path is to 0 °, the longer the driving time of the resist plate 601 according to the thickness of the sheet becomes.
Since the difference in the time until the detection by the OP sensor 315 increases, the accuracy of detecting the sheet thickness is higher than in the first embodiment.

As described above, according to the present embodiment,
As in the above-described embodiment, the thickness of the paper itself can be detected with a simple configuration, thereby eliminating the trouble of designating the thickness of the paper from the outside, and further reducing the thickness of the paper. Corresponding fine control is possible.
Therefore, the image forming operation according to the thickness of the sheet can be performed by the apparatus. Furthermore, since it has a simple configuration, there is little influence on the size and cost of the apparatus.

[Third Embodiment] Referring to FIGS. 8 and 9,
The printer according to the third embodiment of the present invention will be described in detail. FIG. 8 is a diagram illustrating the operation of the paper thickness detection mechanism in the printer according to the third embodiment. In FIG. 8, reference numeral 801 denotes a paper thickness detecting arm which is a rotating means;
Denotes a phase sensor as a phase detecting means for detecting a predetermined phase of the paper thickness detecting arm 801.

In FIG. 8A, S is a sheet, and the direction of the arrow in the figure is the transport direction.

FIG. 8B shows a state in which there is no sheet on the conveyance path in the above-mentioned sheet thickness detecting mechanism.

FIG. 8C shows a state in which the sheet S is being conveyed along the conveying path in the above-mentioned paper thickness detecting mechanism.
As shown in the figure, when the paper is conveyed from the right, the paper thickness detection arm 801 is rotated clockwise (in the direction of the arrow), and when the paper approaches a predetermined position, the phase sensor 803 is turned on by the paper thickness detection arm. 801 is detected.

FIG. 9 is a diagram showing paper thickness detection in the printer of the third embodiment. 9A is thin plain paper. While the paper Sa is being conveyed, the top sensor 315 detects the leading edge of the paper Sa.
At 803, the paper thickness detection arm 801 is detected. S in FIG. 9B
b is thick plain paper. During the conveyance of the sheet Sb, the top sensor 315 detects the leading end of the sheet Sb, and after a lapse of time tb, the phase sensor 803 detects the sheet thickness detection arm 801.

As shown in FIG. 9, after the top end of the sheet is detected by the TOP sensor 315, the sheet thickness detection arm 8 is detected by the phase sensor 803.
The time until 01 is detected depends on the thickness of the paper.
tb, and so on. Using this, the thickness of the sheet is determined.

As described above, according to the present embodiment,
As in the above-described embodiment, the thickness of the sheet itself can be detected with a simple configuration, thereby eliminating the trouble of designating the thickness of the sheet from the outside, and reducing the thickness of the sheet. Corresponding fine-grained control is possible.
Therefore, the image forming operation according to the thickness of the sheet can be performed by the apparatus. Furthermore, since it has a simple configuration, there is little effect on the size and cost of the apparatus.

[Other Embodiments] As in the above-described embodiment, it is not necessary to determine the sheet thickness in two steps. For example, a sheet thinner than plain paper is discriminated and the temperature of the fixing device is adjusted. If the target temperature is set lower than that of plain paper, sufficient fixing properties can be obtained, which can contribute to energy saving.

Further, it is not necessary to limit the image forming control variably set according to the paper thickness to the target temperature for fixing unit temperature control. For example, Japanese Patent Application No. 10-290316 proposes a method of variably setting a jam detection margin according to a paper thickness instructed from an external device. Alternatively, the jam detection margin may be variably set. Alternatively, the sheet conveyance control may be variably set according to the detected sheet thickness. That is, for example, as in the fifth embodiment of JP-A-6-115792, the present invention may be applied to control of curl removing means.

In the above-described embodiment, a printer is exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, another image forming apparatus such as a copying machine or a facsimile apparatus may be used. A similar effect can be obtained by applying the present invention as a sheet thickness detecting device of the image forming apparatus.

In the above-described embodiment, the electrophotographic method is exemplified as the recording method. However, the recording method is not limited to this, and another recording method such as an ink jet method may be used.

In the above-described embodiment, the scanner unit is used as the exposure means. However, the present invention is not limited to this. For example, an LED array may be used.

In the above-described embodiment, as a process cartridge detachably mountable to the apparatus main body, a process cartridge integrally including a photosensitive drum and a charging means and a developing means as process means acting on the photosensitive drum is provided. However, the present invention is not limited to this, and may be a process cartridge integrally including any one of a charging unit and a developing unit in addition to the photosensitive drum.

Further, in the above-described embodiment, the configuration in which the process cartridge including the photosensitive drum is detachable from the apparatus main body is exemplified. However, the present invention is not limited to this. For example, each component is incorporated. The device or a device in which each component is detachable.

[0068]

As described above, according to the present invention,
With a simple configuration, the thickness of the sheet itself can be detected. Thus, there is no need to specify the thickness of the sheet from the outside. Also, since the thickness of the sheet itself is detected, fine control corresponding to the thickness can be performed.
Therefore, the image forming operation according to the sheet thickness can be performed by the apparatus. Furthermore, since it has a simple configuration, there is little influence on the size and cost of the apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram of a printer system including a printer controller and a printer engine according to a first embodiment.

FIG. 2 is a mechanical configuration diagram of the printer according to the first embodiment.

FIG. 3 is an electrical configuration diagram of the printer engine according to the first embodiment;

FIG. 4 is a diagram showing registration of plain paper and thick paper in the printer according to the first embodiment;

FIG. 5 is a flowchart showing a procedure of registration, paper thickness detection, and fixing unit temperature control setting in the printer of the first embodiment.

FIG. 6 illustrates an operation of a registration mechanism in the printer according to the second embodiment.

FIG. 7 is a diagram illustrating registration of plain paper and thick paper in the printer according to the second embodiment.

FIG. 8 is a diagram illustrating an operation of a paper thickness detection mechanism in a printer according to a third embodiment.

FIG. 9 is a diagram showing sheet thickness detection of plain paper and thick paper in the printer of the third embodiment.

[Explanation of symbols]

 101 ... display 102 ... host computer 103 ... printer controller 103a ... display section 103b ... operation section 103c ... CPU 103d ... ROM 103e ... RAM 104 ... printer engine 201 ... body section 202 ... optional paper feeder 203 ... front cover 204 ... MPT 205 … Flag 206… MPT paper feed roller 207… PCT 208… Flag 209… PCT paper feed roller 210… OPT 211… Flag 212… OPT paper feed roller 213… Transport roller 214… Flag 215… Register roller 216… Flag 217… Process cartridge 218 primary charging roller 219 photosensitive drum 220 developing cylinder 221 transfer roller 222 scanner unit 223 motor 224 polygon mirror 225 folding mirrors 226a, 226b transport belt 227 fixing roller 228 pressure roller 229 Flag 230: Discharge roller 231: Face-up tray 23 2 ... paper discharge roller 233 ... face down tray 234 ... upper door 301 ... electric circuit unit 302 ... microprocessor 303 ... core 304 ... CPU 305 ... ROM 306 ... RAM 307a to 307d ... GA 308 ... MPT paper presence sensor 309 ... MPT feeding Paper roller drive solenoid 310… PCT paper present sensor 311… PCT paper feed roller drive solenoid 312… OPT paper present sensor 313… OPT paper feed roller drive solenoid 314… Main motor 315… TOP sensor 316… Discharge sensor 317… Interface 318… Switch 319 ... Switch 320 ... Jumper 321 ... External interface 322 ... Electrical circuit 323 ... Electrical circuit 324 ... Electrical circuit 325 ... Fan 330 ... Pre-registration sensor 331 ... Registration roller drive solenoid 601 ... Registration plate 602 ... Transport roller pair 801 ... Paper thickness Detection arm 802… Rotating axis 803… Phase sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H033 AA47 BA30 BB01 BB28 CA04 CA07 CA16 CA30 3F048 AA02 AA05 AB01 BA06 BB02 CA02 CC03 CC11 DA07 DC00 3F102 AA02 AA11 AB01 AB02 BA02 BB02 CA01 CB07 DA05 EA02 FA08

Claims (7)

[Claims] An abutting means for abutting the conveyed sheet; and a detecting means for detecting the sheet at a downstream side of the abutting means, wherein the abutting means contacts the sheet according to a thickness of the sheet. The contact position is different, and the sheet thickness is detected from the time difference until the sheet is detected by the detection means after the sheet is brought into contact with the contact means. Sheet thickness detector. 2. A sheet thickness detecting apparatus according to claim 1, wherein said contact means also serves as a resist means for correcting skew of the sheet. 3. A detecting means for detecting a conveyed sheet, and a phase detecting means for detecting a predetermined phase of a rotating means rotated by being pushed by the sheet passing through the detecting means, The rotating means is configured so that the contact position varies according to the thickness of the sheet, and the sheet thickness is determined from the time difference between when the detecting means detects the sheet and when the phase detecting means detects the rotating means. A sheet thickness detecting device configured to detect the sheet thickness. 4. An image forming apparatus for forming an image on a sheet, comprising: the sheet thickness detecting device according to claim 1; and a sheet thickness detected by the sheet thickness detecting device. An image forming apparatus, wherein image forming control is variably set in accordance with the setting. 5. The image forming apparatus according to claim 4, wherein the image forming control variably set according to the sheet thickness is temperature control of a fixing unit for fixing an image on the sheet. apparatus. 6. The image forming apparatus according to claim 4, wherein the image forming control variably set according to the sheet thickness is sheet conveyance control. 7. The image forming apparatus according to claim 4, wherein the image forming control variably set according to the sheet thickness is sheet jam detection control.