GB2043929A

GB2043929A - Photocopying

Info

Publication number: GB2043929A
Application number: GB8005697A
Authority: GB
Original assignee: ORMIG
Current assignee: ORMIG
Priority date: 1979-02-23
Filing date: 1980-02-20
Publication date: 1980-10-08
Also published as: JPS55126259A; DE2907410A1; GB2043929B; FR2449909A1

Abstract

In a line-by-line electrophotocopier employing stationary platen 1, masking belt 10 below platen 1, and scanning light source 4 supported on carriage 2 together with mirror 3, carriage 2 also supports rollers 14 and 15 which hold belt 10 against platen 1 during scanning. Rollers 14 and 15 have a covering of foam rubber. A soft brush may alternatively be employed. Carriage 2 also carries a transparent plastics filter plate 16 between light source 4 and platen 1. <IMAGE>

Description

SPECIFICATION Improvements in or Relating to Electrostatic Copying Apparatus The present invention relates to electrostatic copying apparatus, in particular apparatus in which an original document to be copied is placed for the purpose of optical projection with its image side downwards on a transparent contact surface.

In a known copying apparatus, a masking belt is guided between a contact surface element and a light-permeable plate arranged parallel to the contact surface at a small spacing therefrom. To ensure unhindered displacement of the belt, the spacing betwen the element and the plate must be greater than the thickness of the belt.

Consequently, the mask belt does not lie firmly against the contact element, and an air gap is usually present between the belt and element.

This has the consequence that the edges of masking zones of the masking belt appear on the copies as line-shaped shadows instead of, as desired, leaving no visible trace on the copies.

According to the present invention there is provided a transparent support element on which a document having marking to be copied can be placed with its marking facing the element, optical scanning means for optical scanning the markings of such document by way of a light beam and transmitting an optical image of the scanned markings for reproduction, the optical scanning means being displaceable to cause such light beam to scan the markings, a masking strip arranged below the support element and displaceable parallel thereto to dispose a mask in the path of such light beam, and pressure elements displaceable with the optical scanning means and arranged to be respectively ahead of an behind such light beam in the direction of displacement of the optical scanning means and to press the masking strip against the support element.

In copying apparatus embodying the invention, the masking strip is pressed firmly against the support element in the region of the document so that the edges of a mask on the strip do not give rise to disturbing lines on the copies.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing, which is a schematic elevation of optical scanning equipment in copying apparatus according to the said embodiment.

Referring now to the drawing, there is shown a glass plate 1 serving as a support surface for an original 7 to be copied. Arranged below the plate 1 are a carriage 2, displaceable parallel to the contact surface during the copying process and provided with a mirror 3 and light source 4, a similarly horizontally displaceable double mirror 5, which reflects the image from the mirror 3 twice and the movement of which is coupled with that of the mirror 3, and a lens 6, through which the scanned image of the original 7 on the plate 1 is projected onto a photoelectric layer (not shown).

The original 7 has lines which are seen in end view in the drawing. Guided along over rollers 8 and 9 underneath the plate 1 is a masking belt 10, which is mounted on reels 11 and 12 on either side of the plate 1. The reels 11 and 12 are connected with a controllable drive (not shown) for the displacement of the belt 10 between individual copying processes into desired positions relative to the original 7. The belt 10 consists of a transparent plastics material with different masks 13-which may be in the form of printed forms-of which at least one can be optically projected and copied together with at least part of the original 7.

The carriage 2 carries rotatably mounted rollers 14 and 15 (seen in end view in the drawing) extending at least over the width of the belt 10 and arranged in front of and behind, respectively, in the direction of displacement of the carriage, the light beam which emanates from the light source 4 and is directed towards the plate 1. The rollers 14 and 1 5 press the belt 10 against the plate 1 so that it lies firmly against this in the region between the rollers. Since the rollers 14 and 1 5 are displaced, in like manner to the light source 4, along the plate 1, the part of the belt 10 to be optically projected is always pressed firmly against the plate 1 so that the edges of the masks 1 3 are not reproduced on the copy paper.

To preserve the belt 10 to the greatest possible degree, the rollers 14 and 1 5 are provided with a sheathing of elastic material, preferably foam rubber. In place of either or each of the rollers 14 and 15, a soft brush pressing against the belt 10 can be employed.

In order to keep the effect of the heat from the light source 4 largely away from the belt 10, a light-permeable plate 16, serving as a heat filter and preferably consisting of plastics material, is mounted on the carriage 2 between the light source 4 and the belt 10.

Claims

1. Electrostatic copying apparatus comprising a transparent support element on which a document having markings to be copied can be placed with its markings facing the element, optical scanning means for.optically scanning the markings of such document by way of a light beam and transmitting an optical image of the scanned markings for reproduction, the optical scanning means being displaceable to cause such light beam to scan the markings, a masking strip arranged below the support element and dislaceable parallel thereto to dispose a mask in the path of such light beam, and pressure elements displaceable with the optical scanning means and arranged to be respectively ahead of and behind such light beam in the direction of displacement of the optical scanning means and to press the masking strip against the support element.

2. Apparatus as claimed in claim 1, wherein at

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or Relating to Electrostatic Copying Apparatus The present invention relates to electrostatic copying apparatus, in particular apparatus in which an original document to be copied is placed for the purpose of optical projection with its image side downwards on a transparent contact surface. In a known copying apparatus, a masking belt is guided between a contact surface element and a light-permeable plate arranged parallel to the contact surface at a small spacing therefrom. To ensure unhindered displacement of the belt, the spacing betwen the element and the plate must be greater than the thickness of the belt. Consequently, the mask belt does not lie firmly against the contact element, and an air gap is usually present between the belt and element. This has the consequence that the edges of masking zones of the masking belt appear on the copies as line-shaped shadows instead of, as desired, leaving no visible trace on the copies. According to the present invention there is provided a transparent support element on which a document having marking to be copied can be placed with its marking facing the element, optical scanning means for optical scanning the markings of such document by way of a light beam and transmitting an optical image of the scanned markings for reproduction, the optical scanning means being displaceable to cause such light beam to scan the markings, a masking strip arranged below the support element and displaceable parallel thereto to dispose a mask in the path of such light beam, and pressure elements displaceable with the optical scanning means and arranged to be respectively ahead of an behind such light beam in the direction of displacement of the optical scanning means and to press the masking strip against the support element. In copying apparatus embodying the invention, the masking strip is pressed firmly against the support element in the region of the document so that the edges of a mask on the strip do not give rise to disturbing lines on the copies. An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing, which is a schematic elevation of optical scanning equipment in copying apparatus according to the said embodiment. Referring now to the drawing, there is shown a glass plate 1 serving as a support surface for an original 7 to be copied. Arranged below the plate 1 are a carriage 2, displaceable parallel to the contact surface during the copying process and provided with a mirror 3 and light source 4, a similarly horizontally displaceable double mirror 5, which reflects the image from the mirror 3 twice and the movement of which is coupled with that of the mirror 3, and a lens 6, through which the scanned image of the original 7 on the plate 1 is projected onto a photoelectric layer (not shown). The original 7 has lines which are seen in end view in the drawing. Guided along over rollers 8 and 9 underneath the plate 1 is a masking belt 10, which is mounted on reels 11 and 12 on either side of the plate 1. The reels 11 and 12 are connected with a controllable drive (not shown) for the displacement of the belt 10 between individual copying processes into desired positions relative to the original 7. The belt 10 consists of a transparent plastics material with different masks 13-which may be in the form of printed forms-of which at least one can be optically projected and copied together with at least part of the original 7. The carriage 2 carries rotatably mounted rollers 14 and 15 (seen in end view in the drawing) extending at least over the width of the belt 10 and arranged in front of and behind, respectively, in the direction of displacement of the carriage, the light beam which emanates from the light source 4 and is directed towards the plate 1. The rollers 14 and 1 5 press the belt 10 against the plate 1 so that it lies firmly against this in the region between the rollers. Since the rollers 14 and 1 5 are displaced, in like manner to the light source 4, along the plate 1, the part of the belt 10 to be optically projected is always pressed firmly against the plate 1 so that the edges of the masks 1 3 are not reproduced on the copy paper. To preserve the belt 10 to the greatest possible degree, the rollers 14 and 1 5 are provided with a sheathing of elastic material, preferably foam rubber. In place of either or each of the rollers 14 and 15, a soft brush pressing against the belt 10 can be employed. In order to keep the effect of the heat from the light source 4 largely away from the belt 10, a light-permeable plate 16, serving as a heat filter and preferably consisting of plastics material, is mounted on the carriage 2 between the light source 4 and the belt 10. Claims

2. Apparatus as claimed in claim 1, wherein at least one of the pressure elements comprises a rotatable roller being resilient in at least a circumferential region thereof.

3. Apparatus as claimed in claim 2, wherein the circumferential region of the roller is composed of foam rubber.

4. Apparatus as claimed in any one of the preceding claims, wherein at least one of the pressure elements comprises a brush.

5. Apparatus as claimed in any one of the preceding claims, wherein the optical scanning means comprises a carriage arranged below the support element and displaceable parallel thereto, and a light source on the carriage for providing the light beam, the pressure elements being mounted on the carriage.

6. Apparatus as claimed in claim 5, further comprising a thermal insulating plate of light permeable material arranged on the carriage between the light source and the masking strip.

7. Electrostatic copying apparatus substantially as hereinbefore described with reference to the accompanying drawing.